Best short riddles

logicwhat am I

Alone I am 24th, with a friend I am 20. Another friend and I am unclean. What am I?
The letter 'X'. It is the 24th letter of the alphabet, XX in Roman numerals is 20, and XXX is a label for movies that are very inappropriate (unclean).
61.35 %
186 votes
cleanlogic

Billy was born on December 28th, yet his birthday is always in the summer. How is this possible?
Billy lives in the Southern Hemisphere.
60.55 %
223 votes
simpletricky

A boy was born in 1955. He just had his 18th birthday today. How did that happen?
1955 is not the year he was born. It was the hospital room he was born in.
60.54 %
110 votes