Midomi

Use Midomi.com to search for music and friends by singing or humming part of a song at your computer. This is great for two reasons: 1) You can find songs even if you don't know the artist or title; 2) You can annoy your coworkers and family. Well, it's great for three reasons: You can also listen to other people sing snippets of songs -- so it's kind of like a social web service for American Idol wannabes. All you need is a microphone. And a computer. And an internet connection. And a Midomi account. And vocal chords. Sing along at www.midomi.com.