Quis!, my dad would should with his hands behind his back. The first son (of 3) to shout "Ego!" would get the treat - chocolate, sweets etc.

Keep that. Come in 'andy even if you never use it. (Work colleague/technician/jack of all trades).

Arsenal!
my dad, whenever anyone sneezed, in tribute to Eric 'n' Ernie

What a der-brain! (Sung to the tune of the Hallelujah chorus)
My dad again, prior to contemporary theories on raisinf kids' self-esteem

[Projoy] Well if we're bringing out child abuse, I used to get called "You silly, twisted boy" (a Grytpype-Thynne line, I believe) by my dad, and my mum's go-to threat to make me behave was "I'll bash your face in", which I've discovered works on my own children (the empty threat, that is) :-)