Well, I went ahead and installed ruby-rvm from ubuntu software center, and I can now advise STRONGLY against doing this.
RVM is supposed to install to the home directory (i.e. home/stephen), but the canonical hosted version installs to /usr, which means you need to sudo before you can install gems and so on.
I have removed ruby-rvm using apt, but am now unable to install RVM the proper way (i.e. using curl from command line) and I get an error stating that I need root privileges to write anything to /usr. What a joke, obviously the hosted version that I have removed, has set some kind of flag which now instructs all future rvm commands to work out of
I have actually removed Ubuntu 11.10 altogether now because I just can't get used to this Unity crap. Trying Lubuntu out instead for now.