Stefan was also sitting through the seminar. He indeed drove me all the way to Berlin and back, and carried my laptop around. If you're one of those who don't understand why people get married, that's why ;-) While I was trying to locate the secretary at the institute, Stefan took photos of the whole building. It is located on a hill in between fields, and features a closed inner yard (not yet on the google maps photo) with some plants, tables, chairs and of course blackboards.
The average age of researchers at AEI seems to be much lower than at typical departments. There is also a strong pipeline going from Perimeter Institute to Golm; we met quite a few people I knew from Waterloo. Bianca Dittrich now leads a group on Canonical and Covariant Dynamics of Quantum Gravity, Daniele Oriti has a group on Microscopic Quantum Structure & Dynamics of Spacetime. My former office-mate, James Ryan, is now in Bianca's group, and Florian Girelli, whose desk I had inherited at PI, was visiting.
All together it is a very lively and active place in the field of Quantum Gravity, and one that will certainly continue to play a leading role.