Darker

Avarice: The player who has the most diamonds (no ties) at the showdown gets half the pot.

Grad Student Funding: After dealing the sixth card, before betting, the highest potential showing hand claims half the pot. That is, your four showing cards plus any card you can claim to have. You can not claim a currently showing card, but you can claim one that has folded.

Katamari: The normal winning hand takes half the pot, and leaves half for the next game of Katamari to be played. The winning player must add one rule that, had it been in effect, would have resulted in someone else winning; these rules accumulate during the evening. The final game of Katamari takes the entire pot.

Volcano: When the betting comes to you, you may sacrifice a face card to the volcano god, and get a new card. If you get another face card, the volcano god is angry, and you must toss in three times the current bet. (This does not count as a raise.) Otherwise, the volcano god is happy, and you get to call for free.