The ones that are really cute are orangutangs. I was taking pics of a young orangutang at a zoo once and the orangutang then imitated me holding and clicking my camera.
The SF Zoo had one that was a hoot. He would play hide and seek with you. He would put a food bucket on his head and spy on you through a hole. If you said "peek a boo" and put your hands over your eyes he would play with you.