This month's update to Inform 7 makes a fair number of improvements to how actions are handled. Besides adding variables to rulebooks, actions, and activities, in 4U65 all of the standard library's actions are now written in I7 instead of pasted-in Inform 6. Oh, and writing actions that work for both NPCs and players has become much easier.
Andrew Hunter has updated Zoom, his z-code interpreter for MacOS X, to play Glulx, TADS and Hugo games. He's also updated the manual.