Yeah, the Hypercard player is totally legal. But the Hypercard development application is about $200. (even so, since it's basically a discontinued platform, all ya havta do is go onto the alt.binaries newsgroups and grab the full version.
Wish like hell they'd kept developing it cause I still use it to brainstorm ideas.
And the graphical interface for doing line drawings and blueprints beats anything else on the market. It's simply laid out but you can throw together a basic floor plan in minutes.