They had a Beatle's theme game for a while. I think they started it on the anniversary of the of Beatles playing at old Comiskey and kept it going. I think it was just dropped it a few years ago. The fact that so few people know about it goes to show how popular it was. It was not nearly as popular as Elvis night which contrary to some of the opinions here is one of the top 5 selling games every year and will continue to be for years to come. While it is no longer original it is still a really fun experience. It's one of the few games my kids insist on attending. For the record I like the Beatles a lot more than Elvis.
I just looked at the cubs promo schedule and it is really impressive. That Babe Ruth called shot bobblehead would be very cool. It will be worth a ton on ebay to die hard Yankees fans. Lot's of throwback items: