TADS

Thanks to the efforts of Iain Merrick and Andrew Pontious, there's a nice HTML TADS interpreter for the Mac called HyperTADS. Near the bottom of the HyperTADS page is a link to the latest version. It's in a StuffIt file. Download, unStuff, and put the resulting HyperTADS executable in a folder on your hard drive. Then throw away the StuffIt file you downloaded and you're ready to go.

Inform/Z-Machine and Glulx

There are two popular z-machine interpreters available for Macs, Zoom and Spatterlight. Both handle Glulx and z-code games.

Zoom

You can get Zoom from Andrew Hunter's pages.

Spatterlight

Spatterlight can be found at Tor Andersson's pages.

Hugo

The latest version of the Hugo interpreter lives in the if-archive/programming/hugo/executables directory of the IF Archive. Look for the wxWindows version of the interpreter hugovnn_wxwin_mac.sit, where nn is the version number of the program. Download and unStuff as per usual.

AGT

Though AGT was originally only available under DOS, Robert Masenten wrote a more portable version of the interpreter and called it AGiliTy. You can download it from the if-archive/programming/agt/agility directory of the IF Archive. Download the MacAgility_n.nn.sit.bin file, where n.nn is the version number of the program. By now I trust you know the drill.