On-air challenge: Every answer is a two-word phrase in which the letter "O" is added at the end of the first word to make the second word. For example, given the clue "pack animal owned by Thomas Jefferson's first vice president," the answer would be "Burr burro."
Last week's challenge: Draw a regular hexagon and connect every pair of vertices except one. The pair you don't connect are not on opposite sides of the hexagon but along a shorter diagonal. How many triangles of any size are in this figure?
These days, we're more likely to see professional athletes on products than protest lines. But it wasn't always this way. In the 1960s, sports stars were often as famous for what they believed as for their home runs.
Back then, many athletes spoke out about civil rights. Muhammad Ali was stripped of his heavyweight title and threatened with imprisonment for refusing to fight in Vietnam, on the grounds of racial discrimination.