An increasingly common spelling mistake. The bastardization of the word "tomorrow". Using this spelling of the word you learned in third grade shows that, indeed, you still belong in the third grade.
Tomorrow
A mythical period in time which everyone knows about but has no memory of.
A lot of people say that it is the day after today and that tomorrow will be here at midnight, but if you actually wait until midnight it is today again.
Often used by people to put off work as the new required deadline will never arrive.
Girl A: Are you going to school tomarrow?
Girl B: ..... you mean tomorrow?
Girl A: That's what I said, tomarrow. So, are you going?
Girl B: ... only to teach you how to spell tomorrow. Do you even have a spell check?
Girl A: I'll download it tomarrow. :D