Topsy Turvy

The phases of each player's turn are reversed. (The phases are, in reverse order, ending, second main, combat, first main, and beginning.)
As long as there are more than two players in the game, the turn order is reversed.

Cheatyface

If Cheatyface is in your hand, you may sneak Cheatyface onto the battlefield. If an opponent catches you right away, that player may exile Cheatyface.
Flying

Cardpecker

Flying
Gotcha — If an opponent touches the table with their hand, you may say "Gotcha!" When you do, return Cardpecker from your graveyard to your hand.

Creature Guy

Gotcha — If an opponent says "creature" or "guy," you may say "Gotcha!" When you do, return Creature Guy from your graveyard to your hand.

Stone-Cold Basilisk

Whenever Stone-Cold Basilisk blocks or becomes blocked by a creature with fewer letters in its name, destroy that creature at end of combat. (Punctuation and spaces aren't letters.)
Whenever an opponent reads Stone-Cold Basilisk, that player is turned to stone until end of turn. Stoned players can't attack, block, cast spells, or activate abilities.

Elvish House Party

Elvish House Party's power and toughness are each equal to the current hour, using the twelve-hour system.

Land Aid '04

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. If you sang a song the whole time you were searching and shuffling, you may untap that land.

Split Screen

When Split Screen enters, shuffle your library and deal it into four libraries. If anything refers to your library, choose one of your libraries for it.
Play with your libraries' top cards revealed.
When Split Screen leaves the battlefield, shuffle your libraries together.

Rod of Spanking

{2}, {T}: Rod of Spanking deals 1 damage to target player. Then untap Rod of Spanking unless that player says "Thank you, sir. May I have another?"

Oddly Uneven

Choose one —
• Destroy each creature with an odd number of words in its name. (Hyphenated words are one word.)
• Destroy each creature with an even number of words in its name.

Ineffable Blessing

As Ineffable Blessing enters, choose a rarity.
Whenever a creature you control with the chosen rarity enters, draw a card.

Pointy Finger of Doom

{3}, {T}: Spin Pointy Finger of Doom in the middle of the table so that it rotates completely at least once, then destroy the closest permanent the finger points to.

Gerrymandering

Exile all lands. Give each player a number of those cards chosen at random equal to the number of those cards the player controlled. Each player returns those cards to the battlefield under their control.

As Ineffable Blessing enters, choose a number.
Whenever a creature you control with exactly the chosen number of words in its name enters, draw a card. (Hyphenated words are one word.)

Gimme Five

You gain 1 life for each person who high-fives you in the next thirty seconds. Each player in an Un-game who high-fives you gains 1 life. (Offer high fives. Don't hit people.)

Gluetius Maximus

As Gluetius Maximus enters, an opponent chooses one of your fingers. (Thumbs are fingers, too.)
When the chosen finger isn't touching Gluetius Maximus, sacrifice Gluetius Maximus.

Once More with Feeling

Exile all permanents and all cards from all graveyards. Each player shuffles their hand into their library, then draws seven cards. Each player's life total becomes 10. Exile Once More with Feeling.
DCI ruling — A deck can have only one card named Once More with Feeling.

Modular Monstrosity

Whenever an opponent casts a spell, you have five seconds to choose a keyword you haven't chosen for a card named Modular Monstrosity today that's been printed on a creature card. If you do, Modular Monstrosity gains that ability. Otherwise, Modular Monstrosity loses all keyword abilities.

Mirror Mirror

Mirror Mirror enters tapped.
{7}, {T}, Sacrifice Mirror Mirror: Choose target player. At the beginning of the next end step, exchange life totals with that player, exchange control of all permanents you and that player control, and exchange cards in your hands, cards in your libraries, and cards in your graveyards.

Question Elemental?

Did you know this creature has flying?
Are you aware that any time you say something that isn't a question, when a player points out this fact first, they gain control of Question Elemental?

Mesa Chicken

Stand up, Flap your arms, Cluck like a chicken: Mesa Chicken gains flying until end of turn.

Atinlay Igpay

Oubleday ikestray
Enwhay ouyay eakspay ay onnay-igpay-atinlay ordway, acrificesay Atinlay Igpay.

Prismatic Wardrobe

Destroy target nonartifact, nonland permanent that doesn't share a color with clothing worn by its controller.

I'm Rubber, You're Glue

When you speak in non-rhyming sentences, sacrifice I'm Rubber, You're Glue.
Say "I'm rubber, you're glue. Everything bounces off me and sticks to you": Change the target of target spell or ability that targets only you.

Head to Head

You and target opponent play Seven Questions with the top card of that player's library. If you win, prevent all damage that would be dealt this turn by a source of your choice. (To play Seven Questions, that player looks at the card, then you ask up to six yes-or-no questions about the card that they answer truthfully. You guess the card's name—that's question seven—then the player reveals the card.)

Magic Word

Enchant creature
As Magic Word enters, choose a word.
Whisper the chosen word: Tap enchanted creature.

Squirrel Dealer

When Squirrel Dealer enters, ask a person outside the game "Do you like Squirrels?" If they do, create a 1/1 green Squirrel creature token.

Knight of the Kitchen Sink

First strike, protection from loose lips (Nothing with an open mouth in its artwork can block, target, deal damage to, or attach to this creature.)

Censorship

As Censorship enters, choose a word.
Whenever a player says the chosen word, Censorship deals 2 damage to that player.

Emcee

Whenever another creature enters, you may stand up and say in a deep, booming voice, "Presenting . . . " and that creature's name. If you do, put a +1/+1 counter on that creature.

Lexivore

Whenever Lexivore deals damage to a player, destroy target permanent other than Lexivore with the most lines of text in its text box. (If two or more cards are tied, target any one of them.)

Clay Pigeon

Flying
{1}, Throw Clay Pigeon into the air at least two feet above your head while seated: If you catch Clay Pigeon with one hand, prevent all damage a source of your choice would deal to you this turn and tap Clay Pigeon. Otherwise, sacrifice it.

As Ineffable Blessing enters, choose Flavorful or Bland.
• Flavorful — Whenever a creature with flavor text enters under your control, draw a card.
• Bland — Whenever a creature without flavor text enters under your control, draw a card.

AWOL

Exile target attacking creature. Then remove it from the game. Then put it into the absolutely-removed-from-the-freaking-game-forever zone.

Slaying Mantis

Just a second (As long as this spell is on the stack, players can't move permanents.)
Slaying Mantis enters by being thrown from a distance of at least three feet.
When Slaying Mantis enters, it fights each creature an opponent controls that it touched as it entered.

Charm School

As Charm School enters, choose a color and balance Charm School on your head.
Prevent all damage that would be dealt to you by sources of the chosen color.
When Charm School falls off your head, sacrifice Charm School.

Miss Demeanor

Flying, first strike
At the beginning of each other player's upkeep, you may compliment that player on their game play. If you don't, sacrifice Miss Demeanor.

Loose Lips

Enchant creature
As Loose Lips enters, choose a sentence with eight or fewer words.
Enchanted creature has flying.
Whenever enchanted creature deals damage to an opponent, that player may say the chosen sentence. If they don't, you draw two cards.

Bronze Calendar

Spells you cast cost {1} less to cast.
You must speak in a voice other than your normal voice.
When you speak in your normal voice, sacrifice Bronze Calendar.

Old Fogey

Phasing, cumulative upkeep {1}, echo {G}{G}, fading 3, bands with other Dinosaurs, protection from Homarids, snow-covered plainswalk, flanking, rampage 2

Entirely Normal Armchair

During your turn, if Entirely Normal Armchair is in your hand, you may hide it on the battlefield.
{0}: Return Entirely Normal Armchair to its owner's hand. Only your opponents may activate this ability and only if they see Entirely Normal Armchair.
{2}, Sacrifice Entirely Normal Armchair: Destroy target attacking creature.

Common Courtesy

Whenever a player casts a spell without asking your permission while casting it, counter that spell.
When a player asks you permission to cast a spell and you refuse, counter that spell and sacrifice Common Courtesy.

Mouth to Mouth

Choose target opponent and target creature they control. You and that player have a breath-holding contest. If you win, you gain control of that creature.

Flock of Rabid Sheep

Flip X coins. For each flip you win, create a 2/2 green Sheep creature token named Rabid Sheep.

Look at Me, I'm the DCI

Ban a card other than a basic land card for the rest of the match. (All cards with that name in any zone or sideboard are removed from the match.)

Keeper of the Sacred Word

As Keeper of the Sacred Word enters, choose a word.
Whenever an opponent says the chosen word, Keeper of the Sacred Word gets +3/+3 until end of turn.

First strike, protection from black borders (Nothing with a black border can block, target, deal damage to, or attach to this creature.)

Staff of the Letter Magus

As Staff of the Letter Magus enters, choose a consonant other than N, R, S, or T.
Whenever a player casts a spell, you gain 1 life for each time the chosen letter appears in that spell's name.