Personally I couldn't be bothered doing birthdays and I don't think anyone else can either. They have popcorn parties for special rewards where they get a handful of popcorn and 10 minutes extra play. The exception would be a fifth birthday at preschool because most kids here Finish preschool on their fifth birthday and start school the next day (or finish the day before and start school on their birthday). The friends kid was at a shared lunch at school as part of some event.