A kindergarten class had a homework assignment to find out about
something exciting and relate it to the class the next day. When the time
came to present what they'd found, the first little boy walked up to the
front of the class made a small white dot on the blackboard and sat back
down. Puzzled, the teacher asked him just what it was.
"It's a period,'' said the little boy.

"Well, I can see that,'' she said, ''but what is so exciting about a
period?''

''Damned if I know,'' said the little boy, ''but this morning my sister
was missing one, Daddy had a heart attack, Mommy fainted, and the man
next door shot himself."