One my Dad used to tell, not sure if it's well known.
A local bum, for the laugh, wanders into a catholic church during mass one day, shouting "I'm Jesus Christ! I'm Jesus Christ!" The priest tells the altar boys to give him a fiver, get rid of him.
The bum thinks 'this is fantastic, off to the church of Ireland next!' Once again, he staggers in, slurring "I'm Jesus Christ, I'm Jesus Christ! Son of god!" He gets another fiver from the reverend and off he goes.
Tipping into the local synagogu…