If the words "More cowbell" mean anything to you, then you need to visit MoreCowbell.dj, a site that lets you add your own cowbell beat and Christopher Walken sound bites to any song.
In a 2000 Saturday Night Live skit that parodied Blue Oyster Cult and VH1's 'Behind the Music,' Christopher Walken played music producer Bruce Dickinson. His iconic phrase uttered in that set--"More cowbell!"--spurred an Internet sensation.
MoreCowbell.dj uses The Echo Nest Analyze API to gauge a song's structure. You can adjust the slider bars to add more cowbell and more Christopher Walken to the songs you upload.