Drupal Association members fund grants that make connections all over the world.
A new beta of Commons distro is out and there's a PDOException issue which happens when you click "Attend" an event then "Cancel":
I tracked it down to this module which doesn't seem to support the latest Entity cache configuration settings. I guessed this as there's a previous issue which provides support but no longer works:
I've attached a patch which removes the error but I'm not sure if you're wanting to cache all the things I set, or if this is indeed the "correct" way to do things, but thought it'd be a start.