Tilestack (in beta) runs Hypercard stacks and lets you create new ones.

I happened to have been at Apple’s press launch of Hypercard lo these many years ago, and built a couple of stacks, including one to introduce Interleaf’s gigantic (at the time) text-and-graphics system. Hypercard was a miracle of generativity: Drag and drop, link things up, learn how inheritance works, and, boom, you’ve got a clickable, words and pictures organism. Is there anything more exciting than discovering a new power to create?

(The Internet is Hypercard times gazillion. It’d be nice to keep it that way.)