My advice (if it won't get you fired): it's better to ask for forgiveness than permission. I think once your superiors see you get 4x as much done as your Perl-loving peers, they'll wonder what's going on.
If that's not a viable option (e.g., code reviews, etc.), then I'd suggest really pushing it with reason and research rather than emotions and religion. Our book should give you some ammo, but there also books like "From Java to Ruby" and others that provide a view of the transition from a number of viewpoints ("From Java to Ruby" is from a manager's perspective). I'd suggest maybe even targeting a few systems/scripts and rewriting them in Ruby to demonstrate the differences. At least, that's worked well for me in the past.
Assaf may have input on this issue, too.