Brightly colored construction
One of the many wonderful things about Dagstuhl is their incredible computer science library. This entire bookcase is devoted to books that have resulted specifically from previous Dagstuhl seminars. And I'm sure that if you pulled together all the individual papers and such that have come out of these workshops it would be many, many shelves.
They also do cool things at each seminar like set out all the books that were authored or edited by participants at that seminar. The authors are encouraged to sign their books, and everyone gets a chance to browse the work of their colleagues.
While I'm at Dagstuhl this year I'm going to try (amidst all the "real" work) to capture something of what the workshop is like and, more generally, what it is to do (computer) science. This is hard because it's not flashy high-action bull-riding kind of work, but it's important, significant work and deserves to be documented. I'm just going to have work harder at it.
I'm also probably going to take more people pictures than I would be naturally inclined to. If anyone finds themself in a photo here and objects, let me know and I'd be happy to remove it.