For my little sister's birthday we went out to dinner and then had some delicious cupcakes (that the birthday girl made herself) and champagne here at our house. For this I made a large banner that I cut letters out of wood-grain contact paper and adorned it with cupcake stickers.
I also sewed a couple other garlands and made some cupcake toppers to match.
Taking my inspiration from here, I covered the house with fresh flowers in vases of various heights.
And of course when families get together, things can get a little silly.