If you haven't done them before then you should definitely go to the Brandenburger Tor/Holocaust memorial/Bundestag. They're right next to each other and worth seeing. I think the hackescher höfe are also worth it for the architecture. A very Berlin thing to do is go to some of the flea markets on Sunday.

In case you like some museums, you can visit the museum island (e.g. Pergamon Museum) or one of the many art exhibitions https://www.berlin.de/en/exhibitions/. C/O Berlin, for example, has interesting topics quite often.

The Technical Museum has some cool exhibits and is right next to some nice parks to chill in, or you can get a beer at Brło afterwards. The German History museum is huge and interesting as well if you're into history.

I think the DDR museum is considered a bit of a tourist trap, but I'm sure a lot of people would still enjoy it 🙂

Depending whats your definition of attraction: https://en.wikipedia.org/wiki/Berghain

I would like to know where I can find a good curry wurst, it's been ages since I've been in Berlin

You generally find those at street corner stalls, I would just keep your eyes open for them.