I've upgraded the site to 3.7.0 as mentioned yesterday, and now all the template upgrades have been completed and everything appears to be in working order. if anyone notices anything out of place or wrong, please let me know.
There's a few new features that I haven't dug into just yet. But, you can check out your profile page (Not the UserCP, though that has changed as well) for social things such as user messaging and social groups.
There's also Thread Tagging now...which lets you tag threads and I imagine you can search or relate threads with Tags.
If you find anything cool, post it here and share it with us all