#rvm on irc.freenode.net
RVM customizes the irb prompt to display the current ruby. You can extend and/or override the prompt setting (see IRB's documentation) in your ~/.irbrc.
For example, to switch back to all Ruby's default behavior add the following line to your ~/.irbrc file:
IRB.conf[:PROMPT_MODE] = :DEFAULT
- You can read all about IRB at ruby-doc.org