The two players in the pot would agree to run the turn and river twice. This was done two or three times in last night's episode. It would come up if one of the players was all in. Sometimes they've already revealed their hole cards and other times it was pre-reveal. The flop comes as normal, then the turn, then the river. The dealer would then push the turn and river cards up a bit and run a turn and river again. If one player won both hands they took the entire pot. If they each won one, they split the pot.
Interesting idea. Don't think I'll be trying it in my home games much.
The other thing they talked about once and played once was when Harman was in the BB. It was something about "hopping in the saddle" or something like that. They tried to expalin it, but failed miserably.