the Westpfalzwerkstatten at Bruchstrasse (beside Mercedes Torpedogarage) is celebrating there anual Fest with lot of life-musik, good food and drinking for good prices and nice programm. Highly recommaned to visit with kids!
here the link (in German) http://www.gemeinschaftswerk.de/de/standorte/westpfalz-werkstaetten/termine
the Werkstatten are a sheltered home to handicaped and disabled people since decates, doing a grait job.
If you find time and good there - have fun!