Hello Clean Supper,

on Sundays there is a session at a pub in Husemannstrasse in Prenzlauer Berg (near Kollwitzplattz), on Thursdays there are two: one in the "Old Emerald Isle", Erkelenzdamm, Kreuzberg; one in the "Anker", Charlottenburger Ufer, Charlottenburg (weekly change between irish and swing-oriented nusicians).
Good pubs wit music, but without sessions would be the "Celtic Cottage", Markelstraße in Steglitz and the "Shannon", Apostel-Paulus-Strasse in Schöneberg (both have websites). Bands to watch out for would be "Inish", "Midnight Court", "Spirit Level", "Overlanders", "Flinkfinger", "Reely" and.... (to those bands I forgot: pardon me).
Concerts are often announced in "Tip" or "Zitty" (both have websites). Feel free to pm me and I will try to give you some recommendations, sometimes concerts aren`t announced properly. We might even meet, if we deceide to go to the same place ;0)
Best wishes
Ernest