The Easiest Kind of Comedy to Write and the Hardest to Write Well
Parody and satire can look easy, but they take a lot of work to do well. Anyone can take some words and switch them around and turn Harry Potter and the Sorcerer's Stone into Hairy Potty and the Dirty Diaper. That's easy. But the premise can't sustain itself. It's just a one-joke idea, and not a great one at that. A good parody takes a lot of time and careful work. Parodies have to be clever to be funny, not stupid. Stupid is easy; clever takes work.
Take a look at song parodies. There are a lot of song parodies that are really forced, and not all that funny. They key to a good song parody is clever writing and musical skill. “Weird Al” Yankovic has both as well as a great ear, and he knows what songs and genres need to be skewered. He has built a very successful career by parodying the right songs at the right time in the right way. His songs are so close to the real thing that if you aren't listening carefully you'd swear you're listening to the original.
To hear the master of the musical mash-up, take a listen to 1991's Weird Al Yankovic — Greatest Hits, Volume 1 and 1994's Weird Al Yankovic — Greatest Hits, Volume 2. Also check out his newer albums Poodle Hat (2003) and Straight Outta Lynwood (2006), or listen to some of his best songs.