Feel like making a game in the vein of CB? Basic source code available upon request (via email).
In order for game to run, you will need an SQL database, Tomcat, and Java. All 3 can be installed for free if you feel like running it locally. Setting up Tomcat is rather easy. Setting up SQL can be a hassle.
To use, you will need some ability with JSP*, a working knowledge of HTML, a working knowledge of Java, and a basic understanding of SQL**.
*Getting enough JSP knowledge to work on the game is pretty easy. One can always just embed java code anywhere where the JSP code is not understood.
**Getting enough SQL knowledge to work on the game is somewhat easy. Mostly you can just copy the existing database entries and queries and just adjust as needed.
Anyhow, a classmate and I wrote a rather simplistic game that could be adjusted into any online RPG you like. It has simple support for stuff like skills and spells but has a lot of stuff hardcoded and doesn't have support for items and whatnot. It is a functioning game prototype, not a full-fledged game. Although it is playable, it is not currently fun to play, mostly because the fight formula is "math.random() > .5" .
Note: Source won't be provided until my grades are out so expect to wait a bit if you request it.