Writing a character sketch

This is the second in a series of short writing prompts inspired by Stephen King's "On Writing":

King's portrait of his large, volatile babysitter, "Eula-Beula," is a character sketch. Many writers use character sketches regularly as writing exercises.  They write about someone they know or knew. Sometimes they quietly observe a stranger and describe their appearance and behavior as well as the personality and biography these things seem to indicate. Pick someone interesting and describe them "to a T." Change their names and a few details if you are concerned that your assessment is too personal or too brutally honest. An interesting character sketch that draws the reader in can help you craft or describe characters as a larger work, or stand on its own as flash fiction (a very short story, usually ranging between 100 and 1,000 words).