I don't know any decent places to drink, but i quite liked Berliner Pilsner, which was about 70cent in the supermarkets.
To do, you definetly need to do a walking tour of Berlin, I think it was Insider Tours i did it with a couple of times, highly recommended.
Also we visited the DDR museum near the Berliner Dom, it got good reviews on tripadvisor, we thought it was fun and informative too.
Potzdamer Platz is nice area to hang out also, lots to do around there. Other than that I went in winter mainl for the Xmas markets, and then in summer we went to one of their beaches on the lakes out by one of the "Sees".
Enjoy, its a great city.