With a little bit of practice, you could dial a phone number directly on the receiver hook. This also worked on touch-tone phones because the switches were all made backwards compatible with the old equipment.
Still, once I figured that out my friends and I would try to call girls we liked using this method. The skill involved and the fact that you'd fail 2/3 of the time would distract you from the fear of actually talking to the girl once you got connected. "Oh, sh*t! It worked. Oh, hi, Rachel. I was playing around with the phone and must've accidentally dialed you."