My two grandsons were born on the same day--but two years apart. They are getting too old for toys, so I decided gift cards to their favorite store were appropriate this year.
For the first card, I made a pull out card and attached the gift card to the back.
For the second card, I made a card with a flap and used a punch to make a space to insert the gift card.
My grandson just turned six, and he loves baseball. I created a baseball birthday card for him that "explodes" when it is opened. The card has a belly band to keep it contained!