Meteor →
Meteor is a JavaScript based web framework that’s currently available as a preview release. It’s early days yet but it looks like it might have a promising future, it’s syntax is clean, it has cool features like real-time data synchronisation and hot code pushes, and it’s being very actively developed. It’s not yet ready to run production web apps of course, it uses the MongoDB API on the client side and therefore isn’t all that secure right now and a lot of the syntax may change in successive versions, but as a toy web framework it’s tons of fun.
If you want to see an example app, I’ve been working on one called gameshelf in my spare time that uses it and there’s many examples on the site that are worth checking out.