Caden sometimes pretends he has a terrible memory, usually when I ask him to do something or he thinks someone else will give him the answers to his homework. Sometimes I can even see he knows how to find the answer, but he will work so much harder to get someone else to do it for him. If I'm not making his homework easy enough for him, he'll find his dad and ask him.
However, one place his memory excels and he'll let you know it is in remembering lines from movies and tv shows. If you're watching a movie and you could pick one line you wouldn't want to be repeated, that would be the one he'd pick as his favorite too. He knows it too, because once he's told to stop saying something or stop being mean, he'll blame it on the show/movie. (That doesn't work for him either though, that just removes tv from the equation for awhile.)
Still thought, I'm impressed at his ability to remember it sometimes. Although when he reveals the plot before we get there in the movie, that part is less than exciting!