Jogging -- A pretty jogging route is along the quays of the River Main, using both sides of the river and the bridges to create a loop. Another choice is the above-mentioned Grüneburg Park, with walkways that are suitable for jogging.
Tennis -- Few of the tennis courts in Frankfurt allow nonmembers to play. A noteworthy exception is the Tennisplatz Eissporthalle, Am Bornheimer hang, 60486 Frankfurt (tel. 069/21239308 or 069/21230810; www.eissporthalle-ffm.de; U-Bahn/S-Bahn: Eissporthalle), which has a half-dozen courts. They're open May to October daily 8am to sundown. The cost is 10€ per hour.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.