You may know when it's Friday and when it's not, of course. Pretty interesting, since Friday marks the start of your (hopefully peaceful) week-end.
Week-end is nice. But doesn't last very long. You may not be sure about it. Is it still the week end? Shall I go back to work? How to make sure?
Yep, dive to your web browser and go to isittheweekend.org, and you may find the answer.
Ok. Saturday to Sunday, you're fine. It's the weekend.