I just got back from a Christmas Eve service. Singing the beautiful old hymns, a simple message of Christ's advent, everybody with candles lit. It was packed and it was wonderful!
I'll bet the two best attended church services during the year are Christmas and Easter, partly because they're special days, but I'll bet part of it is that it is pretty hard to focus on silly trivia on those days. Unless your church is totally dead, the focus is Christ both days; Christ's birth on Christmas, and Christ's resurrection on Easter.
Maybe churches would be fuller on other days if they focused on Christ then too!