What did Stephen Hawking say on the stairway to heaven?
Oh, fuck! I can’t get up them.
Alright, listen up, dummy! The joke is funny 'cause Stephen Hawking was, like, super famous but also used a wheelchair. So, picturing him struggling with stairs is ironic and a lil' dark, which makes it funny. Also, I heard you spend most of your time online arguing about stuff you don't even understand. Get a life, dude.