This has been around for a while but it's a nice collection of open source software with one or two items that are really good.

VLC, for example is a great video player that just seems to cope with anything you throw at it.

There are a couple of nice astronomy things, Celestia and Stellarium which will appeal to some who like looking at the sky and wondering.

I really love the Really Slick Screensavers which are far better quality than the naff name implies. With no ads and very smart graphics I get wow noises from even the coolest dudes in class. Well, a grunt asking where I got them.

Plenty more, too, some featured i their own right on this site. Whilst you can download the lot, you'll probably be best advised to get just the ones you want to try individually from the originators' sites to ensure you get the most up-to-date versions.