Some of the area's finest events and conferences can be found at Messe Essen. Look up its schedule and see if anything is on while you're in town.
Lots of visitors to Ruettenscheid have this events and conferences venue on their itinerary. But Messe Essen is just one of many places worth a visit in the area. If you've got more time on your hands, Zollverein Coal Mine World Heritage Site will keep you amused.