Personally, I'm not a fan of Stampin' Up! (I'm just not a stamper, really preferring the flexibility of designing digitally on the computer), but I found a series of videos by a Stampin' Up! representative who has some clever ideas for interactive cards.
Here's one of her tutorials for a Secret Window Slider:
I am currently working on a set of Circus invitations (which are proving to be some of my most popular invitations). The mom I'm working with requested coordinating thank you notes. I sent her a photo of the simple folded card thank yous that I had used for the twins' party last summer, but these aren't "fancy" enough.
I've adapted Dawn's technique to a thank you note. See below for photos showing the mechanics of this card. (note: I'm not done with adding graphics to it yet. While I like the tiger and the sign that it is leaping over, the plain blue wrapper isn't doing anything for me. I intend to print circus graphics on white cardstock to replace the wrapper.
So the idea is that the recipient receives an item that asks: "Guess who thinks you're awesome?"
When they pull the tab (which will be decorated and marked with a handy arrow), they will reveal the child's photo, at the same time popping up the tiger unexpectedly and also revealing white space on the pull out tab upon which someone can add a personalized message (alternatively, the tab can say something like "Joseph does, that's who!" and I can leave a blank area on the back where a message can be added).
I'm pleased with how smoothly this mechanism works.