Any kid who grew up in the late 80s/early 90s should know the Teenage Mutant Ninja Turtles.

Like most kids from that era, my first exposure to the characters was not the Kevin Eastman and Peter Laird comic series but the syndicated cartoon series (CBS would broadcast the later seasons on Saturday mornings). The Turtles are one of the most successful brands of all time. Action figures, video games, movies, t-shirts, bed sheets, etc. Lord knows that I had a bunch of the figures and all of the videogames for the nes, snes, and gameboy. I also had the board game, ate the cereal (it came with those cool turtle shaped bowls), and the turtles wristwatch.
The first turtles live action movie is one of my favorite films from my childhood. I think it still holds up today (somewhat). The sequels on the other hand.......
With a new animated series coming out soon, a new ongoing comic series, and possibly a new movie (hopefully not the Micheal Bay script), it seems like the turtles aren't going anywhere.