If you have a flute of Champagne and a raisin and you're really bored, you can plop the raisin into the glass and watch it "dance." This movement is due to the repeating accumulation (causing the raisin to rise) and loss (causing the raisin to drop) of carbon dioxide bubbles on the raisin's irregular surface.
The first time I saw this trick was on the first day of my 7th grade science class, when my teacher showed us a glass of translucent yellow-greenish liquid containing a few dark, bouncing blobs. She insisted it was a glass of urine with swimming bugs in it. While she was probably trying to teach us some kind of scientific property (besides see how gullible 7th graders are), most of us were distracted by the "urine and ants" thing. Thankfully, it was just Mountain Dew with raisins in it. The lessons of the story were that raisins dance in carbonated liquids, and you shouldn't always trust your teachers.
Watch the video of the raisin in the Champagne after the jump.
Raisin Dancing in Champagne