Dear 100 Hour Board,
What is always accelerating but never changing speed? This is a test to see how smart you all are because this is no riddle, it can be proven.
If you're going to attempt to challenge the omniscience of the 100 Hour Board, I suggest choosing a question that can't be answered by anyone who took physics in high school.
If I assume that you are using "speed" as a synonym for "the magnitude of the velocity vector," then objects in circular motion are constantly accelerating (because they are changing direction) even though their "speed" isn't changing.