Bit late now for last night, but it depends on what you are looking for. There's a million and one places that are great on a Saturday night.
Are you talking bar or nightclub?
For example, last night we were in:-
Dreigroschenkeller ... for a few bottles of the wonderful
Isar Plop
Negroni ... for a couple of cocktails
Cafe Wienerplatz ... for a bite to eat
Prager Fruhling ... to drink cheap bottles of Augustiner and dance to "Love Cats" apparently
Tresnjewski's ... to meet a group of French people. Also, because I was too sober and about 10 years to old for Prager Fruhling
For me that was a great night out. Largely to do with the group of people I was with. So mention the kinda stuff you like and I'm sure people will help out with a few suggestions.