Rushing through some poker hands
Basically it's online poker combined with a teleporter, as you are immediately whisked away to another table -- and a fresh poker hand -- as soon as you fold your current hand. (You can even hit the "Quick Fold" button and not even wait your turn -- you'll be whisked away although I don't think it passes that extra information on to other players, who will see you still seated until the end of the hand).
One of the tables I was at played at an average of 278 hands per hour! Incredible!
Drawbacks I think are obvious include never really being able to set up hands or analyze opponents. It's more like a tournament when the tables get busted and you're placed against a new handful of opponents.
It's also very dizzying -- you do more hands but it can be harder to keep up with them. Apparently you can "multitable" your rush poker session by re-joining the rush poker lobby.
I wonder if it's mainly for action junkies who can't sit still for very long.