Being a geek of a certain age, I've spent a lot of time with a Rubik's Cube. In fact, I spent essentially the entire summer of 1980 twisting a cube. I still have a cube on my desk, and can still solve it. Doesn't matter. I've got nothing on the cube fanatics out there on the web:

• Twistypuzzles.com has a staggering array of puzzles on display.
• Speedcubing.com is devoted to honing cube solving skills for speed. They also get into esoterica like building Siamese cubes!
• Rubik's Cube Art showcases the craft of creating mosaic-like banners of stacked cubes.