Chrome: Want to play some music with friends who live across the country? You could painstakingly record and send tracks back and forth. Or you can use Google's new JAM with Chrome, a web app that allows you to play music in your browser with up to three friends.
JAM with Chrome works a lot like the mobile versions of Garageband. You pick your instrument, invite your friends with a URL link, and start playing together. You have a selection of 19 different instruments, as well as both "easy" and "pro" modes of playing. You can't save your creations for later, but as a quick way to instantly work through a music idea in your browser, it could come in handy.