Linux

http://tartley.com/?p=1267 Git is simple!

http://sysadvent.blogspot.com/2010/12/day-15-down-ls-rabbit-hole.html Tracing the steps needed to run ls.

https://10.cloud.ubuntu.com/ Try out the server version of Ubuntu Linux for free on a VPS.

http://www.debian-administration.org/article/Recovering_deleted_images_from_flash_cards Photorec can help you recover deleted or damaged photos off a digital camera memory card.

http://www.andlinux.org/ A port of Ubuntu Linux to Windows. This is a direct port and does not include any type of emulation.

http://geektechnique.org/projectlab/781/slurpr-the-mother-of-all-wardrive-boxes Homemade project to leech from multiple open wireless networks for a faster connection.

http://video.google.com/videoplay?docid=7707585592627775409# A documentary on the Open Source movement.

5/18/07 Gil's LotD
http://wikipediafs.sourceforge.net/ Read and edit Wikipedia as a filesystem! For Linux, of course.
http://www.psstpassiton.com/ Different teams work on designing and creating the same film in separate steps.
http://www.fakeisthenewreal.org/subway/ Subways all drawn to the same scale, very cool.

4/12/07 Gil's LotD
http://www.museumofhoaxes.com/worstaprilfools.html
The worst April Fools jokes.
http://www.mensjournal.com/healthFitness/0601/napping_power.html
Tips on power napping.
http://www.tuxmachines.org/node/14738
How to get Knoppix installed on a USB key. Cool beans.

http://www.extremetech.com/article2/0,1697,2102559,00.asp Using Google Earth to study data from the US Census.
http://ubuntuforums.org/showthread.php?t=376283 A guide to setting up Ubuntu as a wireless router, but should work for most distros and systems with a bit of tweaking.