This poem by Jef Raskin includes several dozen exceptions:

"I before E
Except after C,
Unless pronounced A
As in 'neighbor' or 'weigh'"
Education is forfeit for reinforcing such rules!
Sound a feisty reveille while eyeing the schools!
Neither will our heirs be agreeing to deceptions
Once seeing, herein, these sufficient exceptions:
We were seized by a feeling
For fleeing on the ceiling
To a leisurely meal
With Keith, Sheila, and Neil
We drank madeira, so foreign, in steins
Along with a surfeit of weird blueish wines
Being foolish, took codeine, ate ancient proteins
Therein guaranteeing these ogreish scenes
Wherein we're canoeing to a new sovereign state
While deicing a kaleidoscope on a hot jadeite plate
And kneeing obeisance to an overseeing king
Our plebeian lips kissed his counterfeit ring.
Then we unveiled their sleight-of-hand trick
Deifying a heifer, with effect atheistic
And falling from the heights with a loud seismic crunch
We reignited the nonpareils we had heisted for lunch.
So I before E
Except after C
Unless pronounced A?
False decreeing, I say!