Firefox has a wide array of add-ons to install to your browser.  There is an add-on for just about anything you can think of.  But in all honesty I found most of them useless on these school computers.  It's either blocked or a waste of space on your browser.  I finally found 15, and they were fairly decent.  Solitare has been my favorite thus far.  But there are others I liked.  The music player that streams music from youtube.com.  I found one that allows you to post straight to swaglr.  Never heard of the website, but it sounds like its filled with swag.