I offer my own room in our shared flat (2 roommates), including a comfortable kingsize-bed, which would be perfect for a couple.
The flat has a fully equipped kitchen and bathroom.
The best: Oktoberfest is just 10 minutes away (by foot)
Unavailable: Smoke detector
Unavailable: Carbon monoxide detector
Be responsible with the furniture and don't party in the flat (especially if you come because of Oktoberfest)!