He wouldn't bet a wet match. (In the old days people who smoked cigarettes (round tubes of tobacco) used little sticks of cardboard or wood called "matches" to light them. A wet match would not catch fire -- that's what they did, normally -- so it was entirely worthless. Thus a wet match would be about the lowest bet someone could possibly make. I guess they aren't as funny if you have to 'splain them.)
Slim just left town. (This means there is no chance of that thing happening. It is a contraction of the longer version, "You have two chances, slim and none, and Slim just left town.")
You missed that shot? A drunk Girl Scout could have made that if you held her up to the table. (This was from a simpler time when people were allowed to laugh at such jokes.) (Stolen from Byrne's book "McGoorty" and McGoorty may have stolen it from Taberski who probably stole it from de Oro who got it from Collender. I'm tracking down the history now. Where's Glen?)
I just tapped the ball. (while retrieving the three balls I just knocked off the table)
Let him in! He's a member. (as the cue ball rolls towards a pocket) (I find this saying really, really obnoxious, probably because it's used far more often against me than by me.)
Good call. (There was a regular at the PH, now passed, who used to say this when you called a shot that had one chance in 43 billion of going. I think he actually believed they were good calls.)
I would repeat a saying attributed to Ralph Greenleaf by Cue Ball Kelly, but it is much, much worse than the drunk GS saying. It involves the Princess Nai Tai Tai. Ralph and the Princess:
Bob <-- who doesn't mind a little chirping during a game, depending