Three cheers for mithril.js! I've used it for a number of things, including a complete rewrite of a heavy old app that used Ext.js. It was very simple to set up dynamic page assembly for very fast and flexible UIs.

I've tried mentioning it to friends in web dev, but they don't seem to be willing -- if they even look at it, they never try it out. At this point, I just shrug and go back to my simple, reliable and fast pages which load in KB instead of MB...