I volunteered at the Louisville Science Center on PI day and there were a number of activities for visitors. An event that attracted a lot of visitor attention was the pie or PI eating contest. Four staff members and one volunteen competed by trying to eat as much whip cream/chocolate pudding pie without their hands in 3 minutes and 14 seconds. The manager of the gift shop won in a close contest with one of the floor managers.
On the third floor where I was working, we had visitors place a number on a color strip that represented part of the number PI (3.14159...). It was printed out to the first 1000 digits and we began to go sequentially down the list. Here is a picture of the early version where the number chain was still making its way past the second floor. When I left, we had about 100 digits in the chain and when I finished volunteering at 4 PM it might have been toward 200 digits and almost to the floor of the 1st level.
The following picture is one of a banner hanging from the 3rd floor.