I made this card for my daughter's 8th birthday this week. The stamp set I used is "Pretty Princess" (SU!)
I found a card with this same "floating center" and I thought I'd try it! It's really easy to do with the right cutters. I used CM's oval cutters to cut out the cake and pink polka-dot peices. You could use any shaped cutters to do this, as long as it fits within the space of your card front.
For the center, I taped the pink ribbon on top of the polka-dot peice first and then taped my cake peice onto the pink oval. Then I ran the ribbon through the eyelets on the card and tied a bow at the top.
Here's a picture of the inside of the card. I stamped the oval with the "Alexa" stamp set, available for purchase here. The party went really well. It was our first party where we invited kids from school (and ones that I didn't know, and their parents didn't know us!), so we were really unsure if anyone would come. She invited 5 girls and nobody RSVPed. I guess people don't do that anymore ??? SO, we went ahead and decorated and held our breath that someone would show up. Turned out 3 out of 5 came!! The girls had a great time. They had pizza, played the Bratz playstation2 Fashion Game, played the Dance Mat, had cake and opened presents, played with our new bunnies and stayed for about 3 hours!! Whew! It was a great time for her. I'm so glad it all turned out. *happy dance*
NOTE: The Alexa stamp set was designed by Melissa Bastow, in honor of Alexa, a 6 yr. old girl who was diagnosed with Leukemia in Feb. this year. The set is based on what she wanted to see in her set! You can read more about this here.