This is one of those hobbies which those who pursued would have done in their teenage years. Well, I missed out somehow (not willing to embrace my geek nature perhaps?) but it won't stop me from giving it a go as a forty year-old man. Is that sad? You know what, I don't care.
As a science-fiction fanatic (and nascent boardgame geek) tabletop war-gaming is right up my alley: good strategic gameplay, great “fluff”/mythos, and some cool imaginary tech to explore and contemplate. Games Workshop have this is spades, with novels (which I did read as a teenager) and a truly epic timeline; Mantic Games has less, I think, but a great gameplay nevertheless.
Let's get painting!