I'm prone to frequently cracking myself up and laughing just because I think of something funny. Some people don't understand this talent. It confounds them. I choose to look at it as a gift to be able to find a joke funny over and over and over again.
The Simpsons, and Homer in particular, are responsible for many of my frequent fits. One that has been cracking me up at odd moments recently is in the episode where Marge begins making sculpture's out of Popsicle sticks. When she makes a huge one of Homer, he is touched:
Homer: Marge! You made me a sculpture of Magilla Gorilla!"
Such a great joke on so many levels. Besides Homer's obvious obliviousness, it's also funny because only Homer would be thinking of Magilla Gorilla...and he's genuinely happy to have a huge Popsicle stick sculpture of Magilla Gorilla. I've been laughing at this for years.
For a joke to be truly great, it has to be funny not only the first time you hear it, but also the tenth time. This is why writing humor is such an art. Another thing this joke illustrates is the way a joke can be so derived from character. What one character says wouldn't have the same affect from another.