Technique Junkie newsletter online. I spotted the bonus online technique - Telescoping Cards - and immediately thought of gears and Steampunk! I had recently bought the Spellbinders Sprightly Sprockets die set, but hadn't had the chance to use them. I had a feeling they would work perfectly with Tim Holtz' Weathered Clock die, and they did. I love it when a plan comes together!
Here's a little video I did showing how it opens:
The supplies I used can be found at Amazon and Simon Says Stamp via the links below.