Memory blocks or one that says DAD- I think this would be great to teach spelling and matching. Have blocks that have only pictures of thing s/people (I. mom, dad, dog) have them find hose pictures and then put the letters in order. And spell.
The design is for a birthday invitation, but it's a great idea for a launch party invitation! Encourage your guests to bring their balloons. They can double as a party game if you put little messages inside of them!