Seven hours later, we're still playing. At one point I was on death's door, but I gained back money and eventually bankrupted my (normally lucky as hell) brother. I was on another bad streak, though, when my brother's friend decided he was tired of playing and started playing Guts for incredible sums of money. In three or four lucky deals, I won all his chips and the game was over. We went to IHOP for breakfast, then I crashed around eight and woke up a bit after noon.
Incidentally, we made up some pretty silly games. ("Okay, it's five-card draw, except your cards are initially dealt to the guy to your left, and he gets to see them and bet based on them before passing them to you..." Or: "Okay, this is 15-Card Stud. Three dealt down, three up, three down, and so on, with a round of betting between each batch of three. Threes and fives are wild.") My crowning achievement in silliness, though, was:
Bizarro Poker (usually used like "Bizarro Five-Card Draw" or such)
The object of the game is to get the worst hand possible. However, a pair or better of aces is better than a bad hand; if multiple people have ace-based hands, the part involving the aces is judged normally, and the rest is judged in reversed order. (A good Bizarro hand would be 2,3,4,5,7; a much better one would be four aces and a two; a perfect hand would be a royal flush. Pair of aces and a two defeats a pair of aces and a three, but a royal flush beats three aces.)