The Harpeth Hills Flying Monkey Marathon happens again this Sunday , but you do n't want to know .
It involves winged monkeys trying to eat you off the road while you race up and down the hills in Nashville 's Percy Warner Park .
The Harpeth Hills Flying Monkey Marathon happens again this Sunday , but you do n't want to know because it involves winged monkeys trying to eat you off the road while you race up and down the hills in Nashville 's Percy Warner Park .