[Pokey]

Probability that a player is dealt AA: 1 in 221.
Probability that a player is dealt KK: 1 in 221.
Probability that a player is dealt AA or KK: 2 in 221.
Probability that a player is NOT dealt AA or KK: 219 in 221.

Probability that six players are not dealt AA or KK: since these are nearly independent events, we can get a rough estimate by taking 219/221 to the sixth power, which is 94.7%. The odds that one or more players is dealt AA or KK will then be 100% - 94.7% = 5.3%. Since the odds of TWO players being dealt AA or KK is going to be about a factor of 100 smaller than the odds of one player being dealt AA or KK, we can just pretend this is the answer.

So, call it five and a half percent or so. The numbers are rough estimates, and calculating it exactly would improve the accuracy very little while being markedly more of a pain in the butt.