Homer Simpson has been in a coma since 1993. In a 1992 episode Homer asks God what the meaning of life is. God tells him that he will have to wait until he is dead, which will be in 6 months. 6 months later a vending machine falls on Homer putting him into a coma. At the end of the episode when Homer comes out of the coma, he is actually dreaming. This explains why his kids never age. The plot points in the show after this incident are also much crazier. For example, Homer goes to outer space, works for a super villain and meets celebrity after celebrity. It has been well documented that people in comas can sometimes hear what people are saying around them. There could be a TV near his room that is close enough for him to hear which is how he knows about modern celebrities.