So far we have been playing that you can discard only one pair, 3 of a kind, or 4 of a kind per turn. But we where wondering if we were doing it wrong. Can you power up more than once if you have two pairs in the same turn?
It should also be noted that you can play multiple ability cards per turn (as can your opponent), and you can do them in any order. You can play an ability, wait to see if your opponent wants to play one, then play another yourself, etc. Or you can just play 5 abilities in a row, if the card description doesn't expressly forbid it.
So, for example, you can activate poker flourish, discard your T, then activate another poker flourish (if you have another T), and so on.
Basically, in the powerup phase and the ability-playing phases, you can do as much or as little as you want.