I estimated:

p(pocket pair): 6%
p(hitting set): 18% (given you have a pocket pair)
p(getting quads) = p(pocket pair) * p(hitting set)^2 = 0.2%

10-person table: ~2% that someone will have a PP and get quads.

2 people doing that on same hand: 2% * 2% = 0.04%

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The math wizzes can give you an exact answer. But, it's very conditional too. I mean, my # includes the time that someone with pocket 2's stays in the hand no matter what the preflop bets, positions, or flop shows. So, in practice, it'll be much less common than even the 0.04% would indicate.

(It's very likely I messed this up big time, but I'm just estimating. We'll see the real answer when a math wiz tells us! [img]/images/graemlins/laugh.gif[/img] )