Are you interested in weekend getaway within China or away from China?

If it's China-specific, you may ask the mod to move your thread over to China Forum.

If you meant outside China, it depends on how long the flights you are willing to take. Japan may be a fine choice. You should be able to get good advice from resident FTers over Japan Forum. Or check out the Hong Kong Forum.

Not sure if tropical weather would be attractive for a Scandinavian like you. Thailand (Thailand Forum) or Bali should be nice. Or if you can hop on the mint direct flights between Beijing and Taiwan, why not pay some visits to Taiwan?

As far as I know, you can enjoy colorful nightlife among all of the places I just mentioned.