A game demonstrating how type is kerned. Might be useful for demonstrations.
If you work with one of the increasing number of sites that use Markdown as an HTML pidgin, this editor might be useful.
Zynga has open-sourced the code that helps animate its Facebook games—specifically, its tools for panning and zooming.
A wiki of software tools to do just about anything related to academia and the Web.
A Yahoo! Pipes knockoff that seeks to be much more user-friendly. Tons of things you can do with various sorts of feeds.
A good Web interface for quickly testing regular expressions.
A development text editor in the form of a Web app.
A Firefox extension that crawls and locally archives Websites. It has some very powerful features.
Takes gnarly compressed JavaScript source and makes it human-readable again. Also available in the form of various browser extensions.
For those who still use the command line on Mac, iTerm offers a much better UX than the built-in OS X terminal.
