My favorite radio station has been playing four-song, listener-created playlists all weekend. I've been enjoying it very much: they've played a lot of songs not in the station's regular rotation, which I always enjoy. (They play the same Sublime song every day at the same time. It's gotten very old.)
If you were to create a four-song playlist, what would be on it? The topic can be anything: your favorite songs, your favorite songs by your favorite band(s); capturing a mood, time of day or season, or a moment in your life--anything. The only limit is that it's no more than four songs.