Equivalent of python's virtualenv

I use Python's virtualenv nearly everyday in my work and was lamenting about the lack of a well made solution on Ruby's side of the fence, that was until I found this great gem: http://rvm.beginrescueend.com. This is the closest I guess Ruby comes to having virtualenv.

I like the elegant way the author of this too approaches installation of rvm short for Ruby Version Manager. It's just a bunch of bash scripts which does some fancy tap dancing with curl but it elegantly works and everything is in your box in a jiffy. I am eagerly installing rvm on my boxes and will report back on my findings.