A "mitzvah" literally means "a commandment," but to "do a mitzvah" can also mean, colloquially, "do a good thing."
Each day, Calanit takes in a "mitzvah note" to her class for her teacher to read. I don't normally write these for her, but today, I was asked to do so. It read:
Calanit honored her Abba [father] by displaying an increased understanding of the rules and regulation of football. She correctly identified the time remaining in the 3rd quarter and she said "Touchdown!" at the appropriate time."