"...it may only be a clean-up, with something much more organized for CITO Day."

Personally, I wouldn't ever worry about planning a big post-cleanup event except in the case CITO Day.  Otherwise, you'll just find yourself planning one after another.  If people want to get together after the quarterly clean-up, it's easy enough to pick a place nearby to meet.  We will be there for the clean-up no matter what is planned afterwards.  I'm sure most people feel the same.  Just my 2 cents!
Dave,
Team DaSH