Not exactly roguelikes, but MUDs [1] are multiplayer games with a roguelike feel, but they are more like the ancestors of MMORPGs, TBH.
A telnet program should basically be enough to start playing. There are some "MUD client" programs that enhance the interface (dunno about MAC OS), and some sites offer enhanced web interfaces as well.
One of the most popular, Aardwolf [2] is very newbie-friendly.
Thanks, I am old enough to know of MUDs "first hand". But what I am looking for is a way to play casually with exactly one friend (who lives hundreds of Kms. from me) and not to spend more than 1 hour in the game at the time.
A telnet program should basically be enough to start playing. There are some "MUD client" programs that enhance the interface (dunno about MAC OS), and some sites offer enhanced web interfaces as well.
One of the most popular, Aardwolf [2] is very newbie-friendly.
[1] https://en.wikipedia.org/wiki/MUD
[2] https://www.aardwolf.com/