Or they could plan their own school carnival as part of learning math. Use thematic units or interdisciplinary units to address topics from multiple perspectives. Use role playing and simulation activities. For example, you could organize a murder mystery for students to play while they read Agatha Christie. Don't use reading as a punishment.
Many students have a low enough opinion of reading without their teachers reinforcing it.
Don't send the message that reading is so awful that you're going to make them do more of it to discourage other behaviors. Don't have a student read out loud if that student is not comfortable reading in front of his peers. Nothing turns a student off of learning like making a fool out of themselves in front of their classmates. Don't always assume students aren't doing their reading assignments because they're too lazy to do their homework. Remember, the point is to get them reading first.