mod_rails
Phusion Passenger — a.k.a. mod_rails — makes deployment of applications built on the revolutionary Ruby on Rails web framework a breeze.
If this works as advertised, I can't imagine how it could not become the default Rails deployment option in a manner of weeks.
I dunno, a lot of us were pretty happy to leave apache behind.
For testing purposes, I moved a couple of small / low traffic rails apps to mod_rails. Until now they perform quite well. Memory consumption dropped significantly. The trade off seems to be a small extra time for spawning an rails instance when there wasn’t a request in some time. But as soon, as the process is up and running, the sites seem to be faster.