If you don't know what Grooveshark is, think Pandora with more control over what music actually plays. You can build an exact playlist and let it run, no wondering what song comes next. In other words, if you want to hear a song, you search for it and play it right away.
The only bummer with this controversial music site is that you can't get it on your smartphones and tablets because the app is rarely approved. Now you can have Grooveshark on any gadget that supports HTML5, like your iPhone. Simply point your browser to http://html5.grooveshark.com and rock on.