I even had fun just dancing outside in the area surrounding the Kaiser Wilhelm Memorial Church where they set up a sound system by a restraunt on even along the sidewalks across the street. There is also a small club across from the Church that stayed open from Thurursday til Sunday. You can even bring along a Large Boom Box play some good Music and start your own little Street Party and make new friends. As far as lodging goes, get your reservations early, all the rooms in Berlin are Sold Out several Weeks and Months in advance. A lot of people just Camp Out in the Tiregarden area but remember this is a large Green Belt and Park within the City not a Campground.
Limited facilities are available there such as water and restrooms.
The Tiergarden Area of Berlin is a very beautiful area, very peaceful and plesent to be in, and a nice area to visit. Respect the City of Berlin and Nature.