If you make/receive a call outside the "unlimited" evenings/weekends window, you will be using your minutes. If you have unlimited incoming calls, then you can receive all calls anytime. If you use more than your plan's anytime minutes, there will be an extra charge ($0.45/min).
Ken is absolutely correct, Simmii. I just want to add that only if you have two plans under the same account, then you can call each other unlimited. Unfortunately this doesn't apply to everyone who had a Koodo account, I wish though :)