Adult coloring books are all the rage right now and why not add the trend to your stampin? Just take a blank piece of white cardstock and some black ink and a line art stamp set of your choice. Start stamping the images randomly all over the front of the cards. I used a Aqua painter to add just a touch of color to the flowers and the bumble bee. The other card is how it looks before you color it.
I used the Happy framelit and adhered it to the front of the card.
Take a look at your stamps sets and give this a whirl.
The more of a line art design the better. Then just fill it in with a little bit of color. Have fun!