XMLHttpRequest Caching Tests
Comprehensive series of browser tests to see what your XHR implementation does in different situations. (If conditional request, etc.)
cashto's blog : It's OK Not to Write Unit Tests
Fairly decent anti-unit-test article (about the strongest and most reasonable I've seen): "There's this theory out there that Agile projects can refactor fearlessly because there's this immaculate suite of tests that can sound the alarm the second the smallest regression gets introduced. But anyone who's actually tried it knows that it's mostly just a fantasy. Unit tests tend to overspecify behavior—they test implementation details that don't matter, rather than fixed contracts that do."
JSLitmus
Very very nice little tool for testing JS performance.
video samples
videos in a whole bunch of different formats, for testing, etc.
SlickSpeed Selectors Test
tests the speed of the javascript selectors of major javascript libraries
Glasnost: Bringing Transparency to the Internet
java app that apparently checks to see if your torrent traffic is being throttled
Canopus - a photoset on Flickr