I don't blame you for fearing the parks!
At the Millenium, 1/2 of my family had the flu, so we stayed by the hotel. Dixie Landings (POR) had a special party in their lounge area. There was a piano player guy, and it basically turned into the "poor man's Jellyrolls." It was a lot of fun, and people were passing out hats and noisemakers. It was very cozy - probably 50 people or less, but it was a lot of fun, and a great alternative.
I'd be surprised if other resorts didn't do the same.
Oh, and a few years back, we went to the party at Atlantic Dance on the Boardwalk. It was great, and we went out on the Boardwalk to watch EPCOT's fireworks.
Denise