this one comes from the end of a drew carey special back in the 90's: there's an old man & an old woman in a nursing home... old man says, 'bet you can't guess how old i am!' she says, 'yeah? unzip your fly!' he does; she reaches in a feels around for a bit, then says: 'you're 83!' he says, 'that's amazing! how'd you know that?' she says, 'you told me yesterday.'