Some games are simple luck (the big wheel, Slots, and other games with very little human element), you wager and hope I'd say Edge handles that well enough. Use an applicable Knowledge skill as a Teamwork Test, add hits to the Edge Test. Add up the 1's and subtract them from the Hits, 1's<Hits= loss of wager while Hits<1's= win, multiply the wager by the net hits.
Other games have a physical human element (Craps, Roulette, and similar), I'd say you get a choice of wager classes. Each class having a threshold and wager multiplier. High Risk (5, x10), Middle ground (2, x2), or Low Risk (1, x1). Only one roll is allowed per wager, if you miss the threshold you lose; make the threshold and multiply the wager by the net hits as above then multiply by the wager class multiplier.
Roulette - Agility(NPC's)+Edge(PC's)
Craps - Agility(or Thrown Weapons, Exotic Ranged Weapon)+Edge
In most card games you are playing against the other players as much as you are playing against the dealer/house. Here, I'd use complementary knowledge and social skills as Teamwork tests, have each player roll the complementary skill tests to build-up a dice pool. These games typically have a buy-in amount as opposed to a wager, you win by collecting the other player's buy-in funds.
- 5-card Stud
- 5-card Draw
- No-Limit Hold 'Em
Each card game would have a different number of betting cycles during which the players roll their social/knowledge skills. Whichever player accrues more net hits in each betting cycle sets that rounds bet, up to the maximum for the game (say, net hits x a percentage of the buy-in), and rolls the rounds net hits adding net hits from this test to the ending Logic+Edge test.
Racing, both animal and vehicle, can also fall into the realm of gambling. I'll think on this and get back to you all.