In about 45 minutes, I taught a young lady from work how to ride a bike. I was probably as excited as her, if not more. She started from having never tried at all, to pedaling around the parking lot albiet wobbly. She grew up in Africa and never had a chance as a kid; at around 6'6" she was afraid of falling and getting hurt... thinking it would be too hard.
That was exciting, I feel like a new dad.