Air Conditioner Randomly Quits

I have a 2006 Toyota Prius w/about 67k on it and until know I have not had any issues with it. Recently the a/c randomly decides not to come on when the car is started. I can change the fan/temp controls on the touch screen and the steering wheel, but nothing seems to get the a/c started. After a few minutes of driving the a/c will turn it self on like nothing happened. It happens at random times and outside temps (live in FL). Any thoughts or suggestions?