I always make the kids cake. They get to pick the flavor and the frosting and the theme ( within reason) I've made ocean themes, cats, dogs, fashion, ect. I can't make super fancy cakes and I don't have wilton pans or anything, but I can usually do something closely to what the child likes.
I always put streamers up for the kidsin the house. These are cheap, like 50 cents a package, and a run them along the stairs, put them on thier door. I like to blow up a few baloons and tape them on the stiars or whatever. For about 2.00 I can make it look festive just for them.
They get to pick a meal. I don't care if it's breakfast, lunch or dinner, but it's thier pick . This year dd picked dinner at a restaurant, but last year she wanted pizza. I'm not the best cook so it's usually someone else's cooking they want.

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They can have a friend party every OTHER year. We usually don't end up having one that often though- they have summer birthdays and it's nearly impossible to find all the friends that time of year- they are all on vacation or camp or whatever.