Lispers are meeting up on a regular basis almost everywhere. But does Berlin have a Lisp user group? If so, where would you start looking for it? Until recently, the only resources available were the mailing lists eurolisp (targeting everyone and no one in particular) and lisp-hh (frequented by Hamburg Lispers).
Now, thanks to Hans, we have our own Wiki and mailing list. For your future Lisp needs in Berlin, we present lisp-berlin: http://groups.google.com/group/lisp-berlin
See lisp-berlin/treffen for Katrin's "Stammtisch", which has been a regular meeting for about a year now.
We would like to organize meetings replacing the Stammtisch later this year, ideally in a place that is not as excessively casual, so stay tuned for more.