Riddle: What occurs once in a minute, twice in a moment and never in one thousand years?
Answer: The letter M
Riddle: If I have it, I don't share it. If I share it, I don't have it. What is it?
Answer: A secret
Riddle: What comes down but never goes up?
Riddle: What can you catch but not throw?
Answer: A Cold
Riddle: How many months have 28 days?
Answer: All 12 months!