They are called My Little Monsters and are from Michaels, but as I don't have access to their store I got mine from Auroradawn Crafts.
I've stamped an image directly onto the card and then stamped again onto white card, coloured the images with Promarkers, cut them out and then stuck them over the image on the card. That way all the stamped details are still there and the colour doesn't bleed through to the inside of the card. The sentiment on the front is from a Ladybug Crafts Ink set which came free with Simply Cards And Papercraft magazine.
The inside is the same on both cards with a large 'Happy Birthday' greeting in Papermania stamps combined with a '4' from Penny Black and a small 'th' from another set of letters.
I'm just in time to enter these for I Love Promarkers challenge #123, which has an 'Anything goes' theme.
** Kate **