Mikes Bike Tour is a great time: http://www.mikesbiketours.com/munich/
When you are done with the Hoffbrauhaus go where the locals drink http://www.augustiner-braeu.de/
It's a 2 min walk from the HBH.
If the weather is not so great check out the German technological museum - you can spend months in there....
Also the BMW veld and museum is worth a trip... It's close the Olympic Stadium.