This may be common knowledge here, but if you're looking for a way to legitimately snag a copy of early Bungie games like Pathways into Darkness and Minotaur, there's a compilation release called the "Mac Action Sack."
Bungie's Mac Action Sack is easy to find on Amazon and eBay, even complete sealed copies, for around 15-20 USD. It contains the Marathon Trilogy, Pathways, Minotaur, and the Bungie published Mac port of Abuse, all in a fetching sack (with a Bungie logo).
I wrote an article on my crummy website with pictures and such, which I will link below if that sounds interesting to ya.
Get yer hands on a sack!