I have a development server running Mac OS X Server 10.5, using Ruby 1.8.6. It's been quite a while since I set this up, but I think I built it with Dan Benjamin's recipe, so it might be a compiled from scratch Ruby, rather than the one that shipped with Server 10.5.
I have some sites in progress using Rails 2.3.8 and 2.3.5, but I would like to try Rails 3. Is there a version of Ruby I can install on the server which will straddle both of those rowboats without pitching me into the river? I don't want to upgrade the other sites, and I don't want to have a bad experience with Rails 3.