Max Headroom and the strange world of pseudo-CGI – I've always been fascinated by cargo cult analog tributes to technology. Maybe my early exposure to Max gave me the bug?
Reidentification as basic science – Arvind does a fantastic job of explaining why the research he does is so important. I love learning more about people from data, and most of the interesting insights come from interrogating it in unusual ways and finding unexpected connections, which is what his work is all about.
A 21cm radio telescope for the cost-conscious – Beautiful geekery. Who doesn't want to map the Milky Way's radio emissions using nothing more sophisticated than a $20 USB TV dongle?
How Google Code worked – An eminently-practical guide to implementing a regular-expression search engine, from the author of the late-lamented Google Code. It even comes with working source code!
3D lightning – Calculating the three-dimensional path of a lightning bolt from two simultaneous pictures taken from different spots.
Pete Warden's blog 