You'll love them or hate them. Their earlier stuff was pretty hard core. After a few years of that, they got more into funky, grooving, almost classic rock stuff. Clutch, The Elephant Riders, and Jam Room are what I consider to be their best albums. They're pro-bootleging (so long as it's done on a trade for trade basis), so there's boots you can trade for/download all over the place. Check http://labproductions.com/clutch/ and http://www.pro-rock.com (their web site) for more info.

Lab Productions has a lot of songs you can download, and it's cool with the band. I've heard some of their newest stuff at recent shows. Sea of Destruction is one badass tune. I can't wait for them to record it.