Thousands of imitations of MAD Magazine have come and gone: Sick, Nuts, Up Your Nose, Blast, National Review, Crazy, etc. The longest running, which is still hanging in there, is Cracked. It started in 1958 and still manages to push out an issue once in a while. Here's a link to the magazine's website. Here's a link to a gallery that claims it will eventually display every single cover from the magazine. And here's a link to an article about the current publisher and the state of his magazine. I admire the endurance and at times, even the contents.