http://www.stumbleupon.com/

I decided to give this stumbleupon toolbar a try the other night and I am suprised at how much fun it is. Many of the sites I have found, I know I wouldn't have if I hadn't used the SU extension. I installed it as an extension in my other browser- the Mozilla suite. Now I may have to add it to firefox as well bescause I have been using Mozilla more lately ( sorry JRV) .

I added this from the extesions page at Mozilla- but i think you can get it from the homepage of SU as well.