Been to Munich a few times, and was able to take the wife and our oldest once. if your kids are into trains, cars, airplanes, the Deutche Museum is perfect. they have a very elaborate model train setup that my 4yr old (i think he was 2 or 3 at the time) could spend all day watching
Englischer Garten is also very cool, and is located in a nice park. Wurstsalat is very good! not too far away from the Old Palace, iirc, which is interesting to walk thru.