Been here for almost a year and a half and I have to call in because of the weather (not taking the risk of driving my RWD car 35 miles in the ice and falling snow when I just recently had an ice-related accident), but I don't know how to call in. Never had the need to. No one ever told me who to call or what number. Probably because they figure the fewer people who know, the better.
Found this website and thread as the first result of a google search.
I'm gonna call HR I guess, since I don't know my sup's number. It's pretty much impossible for me to make it to work today so whatever, I gotta call someone and if it's not the right person, they can deal with it.