cal is great, but I never remember it exists. I always (OSX) go up to the menubar datetime, get annoyed that there's no kind of simple calendar underneath it (just wrap cal!), then go hunting for Google Calendar. I guess I just don't think of that kind of program as a built-in command-line one.
I feel you, having used Linux (and I guess Windows) a lot longer than OSX this gets me every time, and every time I wonder why such a simple and useful feature was omitted.