Whether you're a motorcycle rider or you just like the idea of heated pants (who doesn't?), this guide from DIY web site Instructables details how to make your own heated clothing without breaking the bank.
To tackle this DIY, you'll need some Teflon wire, copper wiring, various connectors, thermal underwear (or whatever clothing you want to fuse your heating elements to) and a battery. The author of the Instructable seems to know his stuff, and the guide is very detailed, but you'll probably need some level of comfort with electronics and soldering if you're going to pull this off successfully — provided you don't hook it up to a car battery, your pants probably won't light on fire.
(Seriously, though, be careful, and proceed at your own risk. We'd hate to hear that someone ended up lighting up their thermals.)
All the parts will set you back around $US50 (which actually seems like a lot until you go searching for heated motorcycle clothing, which can sell for as much as $US150). If you give it a try—or maybe you've just bought a pair of heated clothing—let's hear how it worked out for you in the comments.
DIY heated clothing [Instructables]