The Irish Petrol Station
The attendant tells him they don't have any petrol.
"Okay", the driver says, "just top up the oil".
"Nope, no oil either", says the attendant.
Annoyed, the driver asks how it can possibly be that a service station has no petrol and no oil.
"Actually, we're just a front for the IRA", replies the attendant.
"Fine then", says the driver, "just blow up the tires".