Polishing your website. Nice overview about the subtleties and details of web design and how those details are what makes great websites.
Honeypot Captcha. It's like the Un-Captcha. Basically you hide the captcha with CSS. Bots see it, Humans don't. You make the successful answer blank. That way normal visitors commenting aren't burdened by it and spam bots will fill it and get caught. Brilliant. I guess this would only really matter if weren't using Askismet, which is the best spam comment catcher ever.
Sitemaps with CSS. Three really nice and downloadable examples of sitemaps. I guess they don't have to be ulgy. Who knew.
CSS Redundancy Checker. This link has been going around a lot. It's a cool idea, but it's name is a little misleading. It actually finds CSS rules that aren't being used rather than CSS rules that are defined and don't need to be. Still cool.