Berserk series was pretty good, and the Claymore series was pretty damn bad. Hellsing OVA V will be out one day... Maybe...
Other than that I've got no idea, unless maybe Kaiji.
Maybe Akagi if you liked Kaiji. I have no idea how to play Mahjong but somehow watched all of it, with a somewhat "I have no idea what happened but saying PON three times must mean he did something badass" mentality. Also whenever people are talking and I don't care about what they're saying, I enjoy entering TENPAI! into normal conversation to gauge their reactions.
Also Akira, Trigun, and Bebop, but everyone's seen those so I don't feel it's necessary to mention them.