With this challenge, it's time to pull out a technique that you don't often do (maybe even prefer not to), but one you would like to try again. Maybe you've wanted to try stitching on cards (or you have and rejected it). Maybe there's a coloring technique or an aging technique. Whatever it is, it's time to give it a fair chance.
For me, it would be embossing on cards - I keep thinking I'm going to pull out my embossing machine and folders, but I haven't in a long time!
For Heidi, it's masking - she loves the look, but doesn't always have the patience to do it. Here's her card with the technique, using a fabulous Prickley Pear tree stamp: