I love this idea and you can really have fun with it! That said, you should g oout of her way to make sure that your plans also help her to look and feel her best the next day, including avoiding alcohol, planning to start earlier so you get plenty of sleep, and making sure she has a really comfortable and quiet place to sleep (sleeping bag parties are great, but not for this night).
Some other activity ideas could include an at-home "spa" party where you can do eachother’s nails, etc (if you aren’t already going to a salon). Avoid full-on facials the night before, though (they should be done at least a week in advance).
I also second the breakfast idea; find out what her favorite foods are but be sure to have some fresh fruits etc available too!
I also have a fabulous baked french toast recipe I love:
Assembled a day ahead to so sauce can soak into the bread. Makes 6 Servings.
1/2 cup (1 stick) unsalted butter
1/2 cup (packed) gold brown sugar
1/2 cup pure maple syrup
1 cup coarsely chopped pecans (optional)
8 Large eggs
1-1/2 cups half and half
1-1/2 teaspoons ground cinnamon
1 teaspoon vanilla extract
1 1-pound loaf unsliced challah or other egg bread, cut into 1-1/4 inch thick slices
Additional warm maple syrup
Stir butter, brown sugar, and 1/2 cup syrup in heaving medium saucepan over medium heat until melted and smooth. Transfer to 13x9x2-inch glass baking dish. Sprinkle pecans over butter mixture.
Whisk eggs, half and half, cinnamon, and vanilla in large bowl to blend. Dip bread slices into egg mixture and arrange in single layer in prepared dish. Pour remaining egg mixture over bread slices in dish. Cover with plastic wrap and refrigerate overnight.
Preheat oven to 350 degrees. Bake French toast uncovered until golden brown and puffed and knife inserted into center comes out clean, about 40 minutes. Cut into 6 pieces. Serve pecan-side up with additional warm maple syrup. This would also be great with fresh berries!