Today is For Pete’s Sake Day. “For Pete’s sake” originated as a substitute for “for Christ’s (or God’s) sake,” and other similar expressions—as using a shortened form of the disciple St. Peter’s name instead was considered less offensive.
According to the Oxford English Dictionary, “for Pete’s sake” came into use more than a century ago and prompted similar sayings such as “for the love of Pete” in 1906 and “in the name of Pete” in 1942.
So now you know.
The Haus of Dcaligari 