Close to Colmar in France there is also a very small town called Eguisheim. According to Wikipedia: In May 2013 it was voted the «Village préféré des Français» (Favorite French Village), an annual distinction that passes from town to town throughout France.
It has a number of wineries where you can have tastings and get some good deals on local wines.
Meersburg is truly charming and can be combined with Konstanz as a lovely day trip from Zurich...make sure to go "up" to the old part of Meersburg and perhaps do a walking tour...same goes For Konstanz... one can easily miss the old town of Konstanz...which is verrrrry charming.
I second Bregenz. Lovely town by the Bodensee. It took us just over 1.5 hours from Otelfingen and it was easy enough to park in the centre. Parked at the Rathaus and it only costed us 60 cents for 4 hours! If you go on a Saturday, you can even enjoy the local farmers' market.
I like Konstanz, it's really close, just after the German border. There are this beautiful island Mainau with a butterfly garden (haven't been there yet, though), a spa (they are renovating the saunas this summer, but the baths are open) and also the Sea Life Aquarium.