Get your passport stamped!

You can find that tourist shop at the East Side Gallery. I thought it was a funny idea, until I learned it was a felony ;) in this forum: Beware of criminal passport stamping!
Hilarious! Please read the answer written by "klaush" - it is the third post on the page.

Beautiful Neukölln - Maybach riverside

What are you up to on a balmy Sunday afternoon in autumn? Leave your digs and take an extensive walk alongside the Landwehrkanal which seperates northern Neukölln from Kreuzberg. On the Maybach riverside - Neukölln - you will find lots of little pubs and restaurants where you can sit outside and watch cheeky little sparrows, frolicing kids, and tourist boats on the slow flowing canal.

Or you cross over to the "nobler" side - Kreuzberg - and walk down the Paul-Lincke-Ufer with its thoroughly restored town houses. You can also sit down and watch boules players or take part in their game.

Yesterday, on my way home, I encountered this most peculiar vehicle packed with eager Neukölln sightseers: