What's your favorite Enigma / Riddle / Sentence Puzzle?

https://slrpnk.net/post/2456342

What's your favorite Enigma / Riddle / Sentence Puzzle? - SLRPNK

Tomorrow is a big event at my university. I’d like to make a fun thing where the people of the Board Game society I am in can try to find me for a riddle, kind of a Where is Waldo in a place where there is a crap tone of people to find the NPC that’ll give them a Riddle (Maybe something to win? No idea how I could do that detail)

'Tis a silly one, but it’s hilarious when it stumps people. Best used verbally:

There are thirty cows in a field, and twenty-eight chickens. How many didn’t?

Answer

Ten. Ten did eat chickens!

My 8 year old daughter got me with this one just yesterday. She was so proud of herself.