In case you're as perplexed by Peanut Butter Jelly Time as I was, here's an explanation from Wikipedia*:
Peanut Butter Jelly Time is a song Internet phenomenon and meme that emerged in the early 2000s. Based upon a song recorded by the Buckwheat Boys, the best known version of the animation (usually distributed as a Flash clip) shows an animated Dancing Banana (itself a well-known emoticon) moving back and forth to the song's repetitive chorus.
*While I've tried to stop using Wikipedia as a source, I think it's appropriate to the seriousness of this particular topic.