There is a harness racing track in Karlshorst Treskowallee 129, S-Bahnhof Karlshorst (http://www.pferdesportpark-berlin-karlshorst.de). Usually the races take place on Sundays.
Before or after visiting the "Gardens of the World", tourists might be interested in climbing on top of the Kienberg a small hill nearby with a view on the surrounding suburbs or to go for a walk in the valley of the Wuhle a small river. More information on the area can be found on the district's official website in German: (http://www.berlin.de/ba-m...)