Informed Consent in Information Technology – An awesome PhD thesis on the problems with those ridiculous license agreements we all click through without reading, and even better with some practical suggestions on how to fix those problems. Apparently Catherine's now looking for more funding to continue her work – am I allowed to dream that Apple or Microsoft might want to bring her on board to fix their EULAs?
TravellerMap – I was never quite cool enough to play the Traveller role-playing game back in the 80's, but they built a fascinating background universe. I stumbled across this site by accident, but the author has built a beautifully detailed interactive map for exploring the whole galaxy, and I'm in awe of this as a labor of love.
Analysis of the 'Flash Crash' – I've always been hooked on odd events, and May's sudden stock-market drop and recovery is one of the oddest I've come across. I don't have enough financial world chops to understand everything in this paper, but it's a detailed technical post-mortem of what actually happened.
Wikiposit – Another rich collection of public data sets, mostly financial, with the site code released under the GPL
Swarm Light – This art installation sends shivers down my spine every time I watch it, and it's a technical masterpiece too, using hundreds of CPUs to control the lights. Make sure you go to 1'30'' in the video, that's where it really starts to take off.