http://www.stereoscopy.com/reel3d/anaglyph-glasses.html – mainly dirt cheap cardboard ones

http://www.rainbowsymphony.com/3danaglyph.html – lots of gimmicky printed ones you can’t buy, plus sunglass and clipon types you can

http://www.3dglasses.net/free3dglasses.htm – this is actually the rainbow symphony guys, but they’ll send you a free pair of the cheap ones for a dollar and a SASE

http://www.berezin.com/3d/3dglasses.htm – has lots of ophthamological jargon I don’t understand, but sells lots of weird looking glasses.

There are other red/blue 3D apps out there, for example Vectrex and Sega Master System emulators that simulate those systems’ 3D goggles using red/blue. Some probably even run under Linux. I made homemade 3D glasses out of an old broken eyeglass frame and some cellophane to play the Vectrex in MESS, but the colors are kind of off since the art shop only had one shade of each color. There are also some fractal programs for Linux that will do red/blue stereo pair viewing, and doubtless someone has a 3D modeling program that’ll do this.