We worked really hard to get through Infocom's Hitchhiker's Guide to the Galaxy. THAT was a fun game.
Other notable favorites were Mail Order Monsters, Fort Apocalypse, Bruce Lee, Jumpman Jr., Castle Wolfenstein, Montezuma's Revenge, Satan's Hollow, Radar Rat Race, the aforementioned Miner 2049er, Phantasie, Agent USA (impossible, but fun), and countless others that I can't remember.