Idea
Popping bubble wrap is the most satisfying useless thing there is, so I put a reward under it. A painting sits behind every sheet, faint through the translucent wrap, and each bubble you pop clears a little more of it. The fidgeting is the same as always, but this time it uncovers something.
Paintings
The works underneath are real public domain paintings, and a finished sheet resolves into the full piece with its own museum placard beneath it. Popping a sheet of bubble wrap turns into meeting a painting you might never have gone looking for.
Gallery
Each painting you finish hangs framed on a gallery wall, and the next one waits wrapped beside it. The more you play, the longer the gallery runs, so the reward for restless hands is a small museum you uncovered yourself.