Originally Posted by ravenheart
That's rarely dictated by the bands.
For instance, it doesn't happen here because all venues insist on an 11pm end except in rare circumstances (i.e Guns N' Roses, or a club night).
This is generally correct. Most venues have curfews to respect - in some places it's 11 (almost all outdoor venues are like this), 11:30, midnight, 1, etc.
The Middle East is basically a bar with rooms and a basement stage and as such seems to be exempt from any "performance" curfew - they close at just about the same time the bars in Cambridge close. It's ridiculous for bigger shows especially since they don't have their own parking lot and they're right on the Red Line. I have yet to understand why they don't try to end their shows sooner.
Some venues in Boston end their shows at different times. If I remember correctly, Great Scott in Allston tends to run a bit late, but not Middle East late.