Via Boing Boing, composer R. Luke DuBois has created a piece called 'Billboard', made from "the 857 songs that have appeared at the top of the charts in the Billboard Top 100 since 1958". From DuBois' website:
Billboard allows you to get a birds-eye view of the Billboard Hot 100 by listening to all the #1 singles from 1958 through the millenium using a technique I've been working on for a couple of years called time-lapse phonography. The 857 songs used to make the piece are analyzed digitally and a spectral average is then derived from the entire song. Just as a long camera exposure will fuse motion into a single image, spectral averaging allows us to look at the average sonority of a piece of music, however long, giving a sort of average timbre of a piece. This gives us a sense of the average key and register of the song, as well as some clues about the production values present at the time the record was made; for example, the improvements in home stereo equipment over the past fifty years, as well as the gradual replacement of (relatively low-fidelity) AM radio with FM broadcasting has had an impact on how records are mixed... drums and bass lines gradually become louder as you approach the present, increasing the amount of spectral noise and low tones in our averages.You can listen here.
...Note that nothing of the original recording is used in this piece; everything that you hear is derived from a statistical algorithm applied to the original recordings. If you know the song used in the average, you may be able to sing the first few bars (or the main hook in the chorus) over the spectral average and find that you are quite in tune with it; in some cases, you may be surprised not to be.