We used to have a megillas taanis. I�ve always found the name funny as it should have been megillas simchos. In either case the idea of klal Yisroel or even an individual celebrating a yearly seudas hodah for an event of significance is clearly based in antiquity. So a seudah on the rebbe getting out of jail certainly has a basis.
That said, if we are honest , we would see that the shuls are not exactly bursting at the seams at night. We don�t live in Vilna of the 1800�s where the baal ha Batim put in a few hours after work(at least not in Flatbush). If you learn a little gemarah you will see that the majority of klal Yisroel has always had the status of �am Haaretz� serious learning and practice was never for the masses, so I�m on board with kosher outlets that have a little ruchniyos mixed in.
