I've played a variant of 9-ball for 8 ball players which is both good for practice and gambling. It probably has a name but I don't know it.
Rack all the reds and a single yellow with the black (All spots + 1 stripe + 8 ball) in a 9 ball formation:
Alternate breaks (as in international rules) if the breaker pots a ball he can nominate reds or yellows, then normal 8 ball rules apply.
Nice variance as the yellow or black is often tied up after the break and you need to run 6 or 7 reds or play good defense, and players can come back quickly with a couple of lucky breaks where the yellow is sitting with easy position to the 8.