One of the best way to keep up with How-Tos that go beyond what I list here is to go to my del.icio.us account on how-to. There are other great resources including Yahoo, AnswerWiki, Askville etc. Of course Google will always help if you know how to ask right.
How to write a video editor in less than 100 lines of (C) code
How to debug Javascript using FireBug (tags: Screencast, Javascript, Debugging)
How to debug Javascript applications using Firebug
How to check syntax errors in JavaScript - Use jslint
How to dynamically create a script on the fly
How to include JS or CSS files in Drupal?