In this video, Stanford math student Ravi Fernando solves a Rubik's Cube while juggling. I'm pretty sure this is legit, unlike Michel Gondry's famous backwards video in which he unsolved a cube with his feet, but presented the video backwards. Fernando's cube shifts are necessarily super-fast, but if you pause the video, you can see them in action. Check this out (and, fair warning, there a mild curse word in the middle from an astonished onlooker):
Okay, so if you want to get started with cube-solving, check out the video. (His notes on YouTube also contain some handy links.) While I must admit that I am not much of a cube-solver (much less a speedcuber), I can at least understand how this works.
Now just do all that while juggling. Can't juggle? This video has basic tips:
If that's not enough Rubik's Cube action for you, check out: How to Solve a Rubik's Cube in Only 23 Moves (including discussion of "God's algorithm"), This Machine Solves Rubik's Cubes (Behold! CubeStormer!), and finally Videos of Amazing Rubik's Cube Solvers.