I've always loved making little sculptures and things like that (like Warhammer type stuff), though I admit I'm not terribly good at it. What I moreso do with 3D art is take existing pieces and weather them. For example, my husband collects Gundams so I make them look all battle torn and gnarly. >:)
I also make silly hemp bracelets, though I don't know if that really counts as art, haha. But if I had more supplies, I'd definitely do more with sculpture and disramas though.