puzzle
Try this interactive sudokuesque puzzle, kindly provided by Muddled Puzzles! 
Katastrophion is a level up from Logikion — if you like sudoku, you'll like this! 
Logikion is a level up from Pandemonion, one of our new interactive sudokulike puzzles! 
A life insurance agent knocks on a door. A woman answers and he tries to sell her a policy. He asks her how many children she has and their ages. She replies: "I have three children, but I will not even listen to your sales pitch unless you guess their ages..." 
A mad robot sets off on a journey mindlessly following a set of instructions. Where will it explode? 

Which gives a tighter fit: a square peg in a round hole or a round peg in a square hole? 

The nth birthday of a very famous mathematician coincides with a year that corresponds to the (n+1)st prime number. Who is this mathematician? 