The BSR comes up with the funniest campaigns to help keep the city clean. Reiner the "bin butler" makes an appearance every once in awhile on Friedrichstrasse or other heavily-trafficked areas to remind people to put their bins in the bin! If you like signs, you'll find more of them at Signs, Signs.
PS: I have a bonus Viennese sign up on my travel blog. And please send me good luck and positive thoughts this afternoon - I have a phone interview (only my second since moving to Berlin).