3D snooker/pool/billiards games are amongst the most engrossing of computer games. And until such time as Jimmy White's Whirlwind Snooker wends its way onto the 8-bits, 3D Pool is just about the best you can get.
It's not all that sophisticated, and it's quite hard to get as precisely lined up for a shot as you'd like, but 3D Pool is a neat game nonetheless.