New to JavaScript? Take a look at my tutorials for JavaScript.
ABC of JavaScript - An Interactive JavaScript Tutorial
Advanced JavaScript Tutorial

Online SudokuA javascript version of the popular japanise number game sudoku. This can be used to play sudoku online.
JasferJasfer or JavaScript Feed Reader is a JavaScript program to read RSS feeds and display it in a HTML file.
Enigma MachineA script that mimics the working of Enigma machines used in World War II by Germany for encryption and decyption of top secret documents.
Software DataBaseA javascript front-end for a XML database. This script uses JavaScript's DOM structure to access a XML file.
Image EffectsWant to create great effects for your images? Just using HTML, DHTML and JavaScript we have created effects that would shame Flash movies.
666 Finding UtilityFind out whether any name has the number 666 encoded in it in two ways.
Temperment FinderFind out your temperment by filing out this questionaire.

Are you using Firefox? I have created a few GreaseMonkey User Scripts.