Just one last thing-- if you can get either of these places for unde $200 a night pre-tax, I think you're getting a GREAT deal. These are actually cheap deals for these type of hotels.

There are two major improv groups, and a number of smaller ones.
Improvboston.com is in Cambridge
Improvasylum.com is in Boston's North End. Both have performaces Thursdays-Saturdays.

I don't know which one you saw, but their performances will likely be similar to what you saw. In my opinion asylum is the better of the two.