I've always wanted to write a Ruby app launcher, like QuickSilver but the language the end user uses is Ruby. So you could define sets of apps like web_dev = [:macvim, :chrome, :iterm], and then web_dev.launch to launch them.

This app tackles that aspect of my launcher, and makes me wonder if my launcher idea is even necessary. Maybe this app is enough. I'm looking forward to it maturing some more (based on other comments)