If there is one S-Bhan metro station that could be considered a nightclub, it'd be the station at Warschauer Straße. Located on a bridge stretching over Berlin's train lines, the outdoor station is a portal to Berlin's best nightlife at many of the nearby clubs and bars on Revaler Strasse.
But for the budget conscious, hang out long enough on this bridge and the party just might come to you. Weekend evenings on the bridge include live performances by DJs and musicians, and the walkways are often crowded with more than just passers-by. These people are here to party, and if you don't want to dance, you'll have to fight your way through the crowd to get where you're going.
Berlin's parties are found not just in the clubs, but on the streets and bridges. And for Friedrichshain, the best outdoor nightlife is found here at the S-Bahn station on Warschauer Bridge.