There were lots of imitators of Mad Magazine over the decades, but the most enduring was Cracked. Sure, I had a few issues of Sick, and Crazy but they just weren't as good. Cracked was nearly as good as Mad, and even stole Don Martin away for a little while. (And while we're at it, here's a Don Martin link and picture from that site!)
Thanks to StupidMonkeyPlanet for forwarding me the following link, that shows Cracked has been reborn on the web! No longer much of a Mad imitator, it's a more adult parody magazine, along the lines of the late, lamented Spy Magazine. And they aren't afraid to get political:CRACKED.com: The Five Biggest Pricks in Congress!