My suggestions

The Hyzernauts are a charitable sports club. Their game is disc golf, which is played with a frisbee and means a lot of fun! They host a golf course at Volkspark Potsdam.
Hyzernauts Disc Golf Club
The Belvedere on the Pfingstberg-hill - the highest point of the city, the best view onto the country and the city. It was brought back to life from a group of dedicated people, the society of friends of the Pfingstberg-Belvedere. "Culture in nature" is their motto.
Society of Friends of the Pfingstberg-Belvedere
The Espressomobil serves coffee fans on its three wheels of an old Italian Piaggio and twice a week it stands in Potsdam: Wednesday and Saturday at the market at the Nauener Gate (9am - 4pm). Great taste, good price and always a nice talk - I really like to spend my time there!
Espressomobil Berlin
Lekker Snoepjes offers fine, handmade pralines and chocolate truffles. The manufactory is situated in the Dutch Quarter and they have a small café in their neat yard. You need to nibble there!
Chocolate Factory Lekker Snoepjes
Potsdam has two wonderful cinemas - the filmmuseum and the "Thalia" in Babelsberg. They screen arthouse movies and smaller films, celebrate premieres and are part of the annual student filmfestival "Sehsuechte" of the Babelsberg Film University "Konrad Wolf". When the curtain is dropped, the "Konsum"-bar inside the cinema is the place to go.
Thalia Arthouse cinema in Babelsberg
The filmmuseum has a permanent exhibition (about the old Babelsberg Film Studios) and shows movie classics on the big screen. Also they have a really rare theater organ and sometimes old silent movies are accompanied with it. Unique!
Filmmuseum Potsdam
The Waschhaus is a cultural center at the Schiffbauergasse at the banks of the Havel river. Once squatters revived the old industrial area and nowadays it´s a trademark of the city - and nonetheless can´t get out of financial problems. Concerts and parties are worth a visit!
Waschhaus Potsdam at the Schiffbauergasse
As well as the Waschhaus the Lindenpark is one of the bigger houses for the youth, but aims on families also. In tough economical times it fights for survival and still hosts good parties.
Lindenpark in Babelsberg
The Theatre Ship anchors near the Old Market and shows theatrical and comedy performances as well as music parties. They even have their own ensemble, the "Stadtspieltruppe".
Theatre Ship near the old market
It is THE student bar for many years and one simply calls it the "Pub". Student prices, good music, usually really crowded and in the center of the city at the Breite Str.
Student Bar Pub á la Pub at Breite Strasse
The student cultural center or "Kulturzentrum" - short "Kuze" - lies within one of the old courtyards of the historic city center and offers not only a bar, but also poetry slams, concerts and even table-tennis tournaments.
Studentisches Kulturzentrum KUZE
The Café Lapis Lazuli is in the Dutch Quarter and has a small, but fine kitchen, a comfy narrowness inside and a relaxed atmosphere on the pavement terrace in the quiet Benkert Str. And they have the handmade organic beer of the Potsdam Brewery!
Café Lapis Lazuli
The "Braumanufaktur" is a brewery in Templin where the beer is brewed by traditional methods and only on a small scale, for instance the "Potsdamer Stange" a strong beer served for hundreds of years in Potsdam or the organic "Biobier" - true enjoyment! They offer brewery tours.
Braumanufaktur Forsthaus Templin