Grooveshark Control Center

Grooveshark Control Center allows you to control Grooveshark by using a drop-down menu and/or hot keys.

The app enables you to perform common actions, such as to jump to the next song or to like/dislike a song, without changing the window.
Additionally, this app comes with a special feature that allows you to ban artists, so they are not played again. Grooveshark does not allow to dislike an artist, just the songs.