I use cafePress for the Anthology.org site store... they are good, prompt, and have never been a bad experience.
The bad side, is you won't make any money, serious money, in short order.
I would approach a local printer, see if they will print it in exchange for an advertisment or other such renumeration. A Calendar is not a terribly complex item (or, i guess it doesn't have to be complex), and they may like the opportunity to make a nice promotional piece for them (and you).
Poll your audience, find out who works where and if they can offer you some benefits...
Hey, guys:
I'm looking to put together a calendar as a fundraiser for the venue this year, and I'm investigating a few online services to create it.
It looks like my likely options are CafePress, Lulu, and Zazzle. Anyone made use of any of these?
I'd love to hear thoughts and experiences...
--simone