Ive been reading a lot of posts about how great Ruby is so I want to try it out for myself; the developer I currently use is jGrasp and I was wondering if that supported Ruby files. If it doesn't can someone direct me to a Ruby developer and compiler please.
"If the facts don't fit the theory, get new facts" --Albert Einstein
You can download the Ruby interpreter from ruby-lang.org if you're on Windows. If you're on Linux and OSX you could also use your favorite package management system like apt-get or port. Here's a nice, compact tutorial for installing Ruby on these mainstream OSes.
As far as IDE's go, Eclipse has a plugin (called RDT), Netbeans has a plugin, and the creator of IntelliJ IDEA have recently released RubyMine. I currently use TextMate myself, which is really just a glorified text editor, because I'm mostly working on small scripts and utilities (I'm working on a Java-based product at the moment). For serious development, however, I'd look into one of the above IDEs.