I didn't get a chance to stay there myself but I find this a great idea! Andreas Strauss re-purposed drain pipes into guest rooms which you can book and called it dasparkhotel.
At the moment there are two of these hotels - one at the Emscher bicycle route at Emscherinsel in Bottrop-Ebel close to Essen in Germany and the other one in Ottensheim at the River Danube in Austria. You can make a reservation online under http://www.dasparkhotel.net and pay-as-you-wish that means as much as you want! Sleeping in a pipe might feel like camping only in a cozy bed and if you on a cycle tour go for it!
I love Munich and I am there at least once a year there!
If I do not stay with friends I stay in Motel One at the Sendlinger Tor. That's right hotel for young professionals with rooms from 69 Euro. The hotel is stylish, has free WLAN and breakfast included and is located in a quiet street in the center of the city with shops, restaurants and bars in front of the door.
From there you can walk to all the tourist attractions such as the Marienplatz, the Hofbrauhaus and the Viktualienmarkt as well as to the Central Station (800m) with a Ubahn and tram stations in front of the door. Visit the Glockenbachviertel with lots of bars, restaurants and boutiques while you are staying there! If you don't get a room there (as it is quite often booked out) try one of the other Motel One hotels in Munich. They are cheaper but not as central as this one.
Another good value compromise is the Hotel Royal with its delicious breakfast, free WLAN and friendly staff. It is close to the Central Station, Deutsches Theater, Stachus, Kaufinger Strasse and the Beer Fest but the area is not as nice.
