Family Circus by Jeff and Bill Keane have been Billy's pun maps, and the kids' wandering-around-dotted-lines. The latter of which are so iconic that they're part of the design of the official Family Circus website and have been endlessly parodied by other cartoonists. This one above, in fact, I found in a Cracked.com article that proposed rather foul alternatives to some Family Circus captions (click link at your own risk)..
Here are more, some original, some parodies. Click on any of them to make them larger, easier to read:
Pearls Before Swine creator, Stephan Pastis
Randall Munroe's XKCD.(the title-text at the original site: "This was my friend David's idea")
Blair Witch Project" theme.