Because every time they get to 69, Miss Piggy gets a frog in her throat.
Rib it...duh!
A dog who can lick himself from across the room
Kermit The Frog's fingers.
They always want to play leap frog with him
Nothing. She had a frog in her throat.
At 69 she always gets a frog in her throat.
68, because when she turns 69 she blows a rod.
Because 69 is a bit of a mouthful.
A nun with a javelin in her throat. (The only joke I can ever recall when asked for one. Told to me by my art teacher in Grade 11. Needless to say, he was my favourite teacher)
She got a frog stuck in her throat at 69.
They need to learn scientific notation to keep track of their n-count.
You use a cow-culator. Or you round them up. Or any other method the commenters want.