We've never been, but I understand that there is a Mother's Day brunch in Epcot on Saturday and Sunday. I called over this past weekend, but the CM said I should call back after the first of the year to get specific details, and to make ressies.
This will be the first time we'll be there for Mother's Day weekend. We're staying at BCV and it should be a great time.
There are usually free Flower Power concerts at Epcot during that time because of the Flower Show. I hope to get to that as well.