Indoor tennis courts in Berlin

I am trying to find somewhere to rent a tennis court by the hour. Have been looking around the web for some time but i still haven't come up with any good place. I am just looking for someplace to play once in a while for fun with some friends so I don't want to become a member or anything like that.

Preferably it should be somewhere near Friedrichshain, however the location is not all that important but it would be perfect if it had courts with rubber surface and not gravel.

Would be really grateful if anyone has any ideas!

Hello, just wondering if you found any info about tennis courts in the eastern part of the city...
I played near Grunewald last weekend and it was nice, but takes nearly an hour transit by bike.

Thanks

Check out this place.

http://www.tc-berlin-mitte.de/tc_berlin_mi.../verein_01.html

I called the other day and apparently they have four indoor courts and two outdoor ones. You can book them for 10 euro an hour and you don't have to be a member.

There's courts on Columbiadamm, where I played yesterday. Indoor, carpet, 13 Euro an hour for non-students, and 10 Euro an hour for students.

I'm looking for a club to join, if anybody knows one.