I know this is flippant, but if you're quite keen to run more than one Ruby web app, why not try ActiveRecord (so you get the Rails ORM) with Sinatra? It's a pretty lightweight solution.
Honestly, I was trolling and expected to be modded down to -8 pretty quickly. It's funny how many of my dead-serious posts get modded down and how many of my trolls get modded up.
I love the clever quips over at Reddit as much as the next guy, but I've come to enjoy HN's higher level of expectation out of its responses. Just because people are modding you up, doesn't mean you shouldn't try to uphold that standard.