We're trying to wrap our heads around this one but aren't getting very far--so maybe our German friends can assist. Microsoft Germany put up a trailer video that you see above for "Windows Phone 7.5 Hotel" which was an event that took place in Berlin on December 15th.
The trailer is mostly CGI and has haunted-house like implications, what with that eerie lightning and all. There also seems to be a map and trying to find something, we're guessing. Next up is another video, evidently form the actual event from folks who traveled to the haunted hotel.
The good part in the video starts at around 2:25 where we start to get an idea of what this looks to be: a type of mass entertainment event where they have actors role-play specific parts and you, the bystander, become a participant in the charade--much like a murder-mystery cruise. This time there's something about the undead, people dressed in hazmat suits, reporters, etc. You can never go wrong with zombies, right?
Yeah, we're pretty baffled too but also intrigued as once again, we're seeing some real creative advertising here. Too bad we're just hearing of it now but hopefully we'll learn a bit more soon enough. Oh and that video is one of three, so maybe the other two parts will shed some light on the matter.
Update: Yup, WP7App.de confirmed with us what we suspected: "That windows phone hotel was a PR event where you had to chase ghosts (ghostbusters-style) with an app on a Lumia." Pretty cool idea.
Big thanks to Heiko R., for the tip!