Go to Gstadt or Prien and take a boat trip on Lake Chiemsee with a visit to Fraueninsel (with the Benedictine monastery and a beautiful fishing village with a schnapps distillery, pottery and lots of nice places to stop) and Herreninsel with Ludwig II's royal palace.
Plan a whole day for this excursion. You will see that it is worthwhile and not just for those interested in history, but for the whole family.
At Prienavera, the adventure pool in Prien, you will experience a real bathing experience with games, fun, excitement and sports. (open: Mon-Fri 10am-2pm and Sat/Sun 9am-2pm)