I just stumbled across some IDE's I never even knew about:

http://arcadia.rubyforge.org/
http://http://www.cloud-ide.com/
http://shiftedit.net/home

I know that there are others out there, but these are what I found 
first.  What's remarkable here is the install process for these IDE's is 
quite different from what I'm (somewhat) familiar with:  Netbeans and 
Eclipse.  

These IDE's are distributed either by gem or through the browser.  Quite 
interesting.



-Thufir