OK, I will make this short because a gazillion of other people will probably blog about the 22C3 for several days or weeks to come... Today (last day) I only attended one talk — Bluetooth Hacking - The State of The Art. Funny stuff you can do with Bluetooth...
All in all it was a great conference. Get the proceedings or browse the list of talks (most of them have PDFs attached) for more details. Videos of all talks should be available anytime soon (I hope!).
Oh, and the 22C3 is probably the only event where you will see such signs (attached to walls by the congress staff!)...