Detective Conan

Puzzle fans who want a whodunit with a kid's face on it will settle in fast, because the murders are real and the clues sit in plain view. A bow tie from Professor Agasa lets the shrunken hero speak in the clumsy detective's voice, so a grown man takes the credit while a grade-schooler names the killer. The noir touches and the small cast do the rest.

Cases wrap up in one or two episodes, so you can drop in almost anywhere; the larger organization storyline only surfaces now and then.