My friends Anibal and Edgar, the developers behind has_many :developers and rubycorner.com, put up a banner ad for MountainWest RubyConf. Not only that, they were the ones who got the ball rolling to do it. Aren’t friends great?
In terms of concurrency, if you’re writing middleware I think you owe it to yourself to look at Erlang. The language itself has the primitives, then there are libraries called the Open Telecom Platform that come with it, that build on those primitives to make reliable software almost simple. It’s never simple, but compared to what you have to do, jumping through hoops in other languages, it’s kind of a no-brainer.