Until recently, without flash or java, the kinds of games you could create tended to be less action-orientated, though some enterprising types had built late 1970s favourites.
JavaScript
Eloquent Javascript
A Modern Introduction to Programming
By treating javascript as a language in its own right, the author has produced a solid guide to learning a language that you might think you already knew.
Learning Jquery 1.3
Learning to Use Jquery to Build Better Websites, Though Examples and Popular Plug-Ins.
Dojo
Using the Dojo Javascript Library to Build Ajax Applications
Using the Dojo to Build Better Websites.
Prototype and Script.Aculo.Us
You Never Knew Javascript Could Do This!
Using the Prototype and script.aculo.us Javascript libraries to simply your life.
Pro Javascript Techniques
John Resig knows Javascript.