My best teaching moments have been related to songs. Students who have gone on to high school e-mail me to get copies of the songs because they love singing them and get a lot of information from them.
Recently I ran into students having a birthday party at a bowling alley. They stood in one of the lanes and sang, very loud and proud, a math song we had been working on in class. It was a fantastic feeling to see them doing math during a party. It's what I love to see and hear.