For three of the cards (for Grandparents), I used Racing Game paper as the background, layered with two of the Checkered Flag cardstock stickers, stamped 'thank you' on the yellow side of the Racing game paper and added a red brad. Easy & Fun!
For the boys that attended the party, I used these old photo cards to add a photo of each boy riding in his Go-Kart, stamp 'thank you' and then added two Checkered Flag stickers on the inside.
Racing Game Paper #1247
Checkered Flags Stickers #5545