Better Grooveshark user script shows lyrics, hides ads, adds current song to tab title
Better Grooveshark also adds the title of the currently playing song to the title of the tab where Grooveshark is open in your browser. This will let you know exactly which song is playing at a quick glance.
But perhaps the most useful feature that this user script adds to Grooveshark is the lyrics sidebar that it places on the right side of the site. Once you hit Search, you'll be able to choose which site Better Grooveshark should get lyrics from. Possible results are then aggregated in a dropdown menu.
Better Grooveshark used to also 'emulate' some features which are normally reserved for those opting for a paid Grooveshark subscription, such as last.fm scrobbling support, crossfading and removing ads (as opposed to just hiding them). However, the developer has recently decided to take those features out of the script in order to support the work of the Grooveshark team.
Better Grooveshark is available from Userscripts.org and should work on Firefox with Greasemonkey, Safari, Chrome and Opera.