A little known biergarten that might be of interest called, Milch-Häusl: http://www.milchhaeusl.de/. It is actually a playground that adjoins a small biergarten and food kiosk in the English Garden. The food is all "Bio" (organic) and it is well worth checking out. They also sell coffee and ice cream and a rather wide variety of food for a small place. They also offer *free WiFi* so take your laptop to the park and sip your cup of coffee while the kids run off some steam!
Also recommend the Hirshau biergarten which is a beautiful bike ride and a lovely walk from central Munich but it will require about a half hour to get there on foot. If you rent bikes it is a great place to pass a few hours while the kids play on the fantastic playground. http://www.hirschau-muenchen.de/
The Chinesischer Turm biergarten also offers a playground downside is it is quite large and gets crowded with tour groups in the summer.
Finally, the best rainy day tip for parents visiting Munich with young kids is to visit the Hofbraukeller http://www.hofbraeukeller.de/(not the same as the infamous Hofbrauhaus but the same brand of beer). It is located near the Max-Webber-Platz U-Bahn stop (U4/U5) and offers free childcare in the playroom and a no smoking section for parents. In the winter months everything on the menu is 5 Euros! It is a traditional beer hall with Bavarian food and quite a bit of history, but a bit quieter than the Hofbrauhaus and more fun for the younger set. (Although, children will love the Hofbrauhaus for the rowdy atmosphere and the oompah band.) The attendants supervising the children at Hofbraukeller appreciate a small tip when you leave. Also note that the playroom is not open in the summer months when the outdoor biergarten is in full swing. The Hofbraukeller does offer a children's menu that would satisfy most tastes.
Cafe:
If you are looking for a nice family-friendly cafe in Schwabing/Maxvorstadt check out the Zeitgeist on Turkenstrasse. Café im Zeitgeist Türkenstr. 74 80799 München Tel: 28 65 9 73. They offer a small section which is really best for those with children under one-year, but the tables outside are fantastic on a sunny day and the kids can run around the courtyard away from traffic.
Museum:
The Deutsches Museum is a wonderful place to take kids of all ages. The basement level is specifically geared for young children and offers family ammenities like diaper changing facilities. www.deutsches-museum.de/en
Outside the Alta Pinakothek in Munich there is a small playground with climbing ropes and sand to dig in. It makes for good incentive for good behavior ("If you behave in the museum you can play on the playground...") and is a nice place to work out some wiggles.
