Riddle: If you look you cannot see me. If you see me you cannot see anything else. I can make anything you want happen, but later everything goes back to normal. What am I?
Riddle: A very famous chemist was found murdered in his kitchen today. The police have narrowed it down to six suspects. They know it was a two-man job. Their names are Felice, Maxwell, Archibald, Nicolas, Jordan, and Xavier. A note was also found with the body: '26-3-58/28-27-57-16'. Who are the killers?
Answer: Felice and Nicholas are the murderers. The numbers correspond to atomic numbers on the periodic table of elements: 'Fe-Li-Ce/Ni-Co-La-S'.
Riddle: Alone I am 24th. With a friend, I am 20. Another friend, and I am unclean. What am I?
Answer: 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 inappropriate (unclean).