Here's why we love open-source software folks. With the release of the Ice Cream Sandwich trunk of the Android Open Source Project code came the ability to build it yourself instead of waiting for it to come from your phone's manufacturer or Google. We've seen several good beginnings, on phones as varied as the LG Optimus 3D or the Samsung Fascinate, but now we've got one that's good enough to use every day for the Nexus S (both GSM and Sprint flavors).
It's a neat mix and match of new source code, binary files from Gingerbread, bits from the Galaxy Nexus, and custom code from other developers. Android dev kwiboo has done an excellent job getting things going, and even facial unlock is working -- as long as you don't have a big bushy beard, that is. As someone who has also been fooling around with the code and flashing my own Nexus S at least a jillion times, my hat's off to him -- I'll say it again, he's done an excellent job. Hit the source link to see for yourself.
Source: XDA-Developers. Thanks everyone who sent this in!