Rare-B-Gone

Each player sacrifices all permanents that are rare or mythic rare, then each player reveals their hand and discards all cards that are rare or mythic rare.

The Countdown Is at One

Players play a Magic subgame, starting at 1 life and using their libraries as their decks. For the rest of the main game, if a source would deal damage to a player who didn't win the subgame, it deals double that damage to that player instead.

Poultrygeist

Flying
Whenever a creature dies, you may roll a six-sided die. If you roll a 1, sacrifice Poultrygeist. Otherwise, put a +1/+1 counter on Poultrygeist.

Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

Party Crasher

Haste
You can attack with Party Crasher once each combat during each opponent's turn.

Squee, the Immortal

You may cast Squee, the Immortal from your graveyard or from exile.

Baron Von Count

Baron Von Count enters with a doom counter on "5."
Whenever you cast a spell with the indicated numeral in its mana cost, text box, power, or toughness, move the doom counter one numeral to the left.
When the doom counter moves from "1," destroy target player and put that doom counter on "5."

Enter the Dungeon

Players play a Magic subgame under the table, starting at 5 life and using their libraries as their decks. The winner searches their library for two cards, puts those cards into their hand, then shuffles.

Well Done

Well Done deals 5 damage to target creature. If that creature is rare or mythic rare, Well Done deals 3 damage to that creature's controller.

Eye to Eye

You and target creature's controller have a staring contest. If you win, destroy that creature.

Destroy target creature with reminder text. (Reminder text is any italicized text in parentheses that explains rules you already know.)

Boomstacker

As Boomstacker enters and whenever it attacks, stack two dice on top of it. (All dice must be stacked vertically, one on top of another.)
Boomstacker gets +1/+1 for each die in its stack.
Boomstacker attacks each combat if able.
When the stack falls, sacrifice Boomstacker.

Devil K. Nevil

Haste
When Devil K. Nevil enters, jump it over any number of creatures. If it clears those creatures, put that many +1/+1 counters on it. (You can see a jumping demonstration at DevilKNevil.com.)

Rocket-Powered Turbo Slug

Super haste (This may attack the turn before you cast it. (You may put this card from your hand onto the battlefield tapped and attacking during your declare attackers step. If you do, you lose the game at the beginning of your next turn's end step unless you pay this card's mana cost during that turn.))

Urza's Fun House

{T}: Add {C}.
{T}: Add {∞}. Activate only once and only if you control an Urza's Mine, an Urza's Power-Plant, and an Urza's Tower.
{7}, {T}: Head to AskUrza.com and click Urza's Fun House.

Farewell to Arms

As Farewell to Arms enters, choose a hand attached to an opponent's arm.
When the chosen hand isn't behind its owner's back, sacrifice Farewell to Arms. If you do, that player discards their hand . . . of cards. (The lawyers wouldn't let us do it the other way.)

Yet Another Aether Vortex

All creatures have haste.
Players play with the top card of their libraries revealed.
Noninstant, nonsorcery cards on top of a library are on the battlefield under their owner's control in addition to being in that library.

The Big Top

{T}: Add one mana of any color that appears on your top. (A top is an outerwear garment worn on the upper body.)

Extremely Slow Zombie

Last strike (This creature deals combat damage after creatures without last strike.)

Face to Face

You and target opponent play a best two-out-of-three Rock, Paper, Scissors match. If you win, Face to Face deals 5 damage to that player.

Blast from the Past

Madness {R}, cycling {1}{R}, kicker {2}{R}, flashback {3}{R}, buyback {4}{R}
Blast from the Past deals 2 damage to any target. If this spell was kicked, create a 1/1 red Goblin creature token.

Trigger Happy

Choose a triggered ability of target permanent. It triggers. You control that ability.