Hypercard came with the old mac OS, and it looks like you can download 2.4.1 at http://www.versiontracker.com/dyn/moreinfo/macos/338 . That said, Hypercard is an old, obsolete technology that hasn't been updated in 7 years. I wouldn't be surprised if it didn't even run right under Classic mode in OS X. For you to need this, you must have a really old computer.
Where can I buy a copy of Hypercard 2.4 for Mac?