Cheat sheets
Sometimes it’s hard to remember certain things about technologies you use when developing a web application. I must admit that I frequent php.net occasionally to remind myself what parameters a function takes. With frameworks, extra php libraries, javascript libraries, and css it becomes increasingly more difficult to remember how to use all of these technologies. In comes the cheat sheet. Cheat sheets are great as a quick reference on how to use common features with a particular technology.
Here is a short list of useful cheat sheets:
Prototype 1.5 - by Jonathan Snook
Mootools r.83 - by Jonathan Snook
Scriptaculous - by Ryan Carter
CSS by Dave Child
You can find more of cheat sheets (PHP, mySQL, Javascript, etc) over at Dave Childs cheat sheet section