Typing for programmers
Even its minified source is very readable! HTML that fits on a single screen, good example of Google Fonts (Ubuntu Mono and PT Sans), defer attrubute on script tag, and other tricks.
Via HN. Someone there mentioned Keyzen, "a touch typing trainer geared towards programmers and others that need to practice with all the symbols on the keyboard." Very nice way to practice weird characters. And it's open source.