Cake. Ice cream. Chocolate. A small present for yourself like a scarf or shoes or book or something. Confetti and noise makers. Breakfast/lunch/dinner with whomever you want. Cookies. A day or night or afternoon or whatever where you get to pick what you want to do. Outing to the park or a museum. Shopping trip. Spa day. Art supplies. Movies. There are lots of ways. You just have to be creative about it and do something you want to do.