Ha that was often one of the party songs for the silly games played at birthday parties when I was in the early primary grades. That and the yellow polka dot bikini song, LOL. When my kids were little a float made with vanilla ice cream and grape soda was called a purple cow. I wonder if your milkshakes were anything similar? It is awesome that you help your kids to throw a random party in the middle of the week. My kids would have loved every minute of that.