40k comes from
www.games-workshop.comTis a table top game involving plastic models which you collect and paint yourself.
They charge an arm and a leg for the damn things but the game itself is ok I guess...
The main thing that keeps it alive is the fictional universe its based on. There's just so much detail on all these different aliens and history of mankind etc.
The novels on offer are usually pretty good reading, it does help if you read some of the history from the rulebook etc. But yeh... $$$$
If you just visit a games workshop store you can have a spy at some of the things they paint. Some of the details they put in is clinicly insane...