I before E

There's a mnemonic to help you remember the correct spelling of ie/ei words:

I before E except after C,
and when sounding like Ay as in neighbour and weigh,
and on weekends and holidays, and all throughout May.

I like this version better than the more commonly heard British and American ones, because in my opinion in demonstrates the absurdity of any rules where there are so many exceptions -- perhaps more exceptions than words that actually follow the rule.

Here are just a handful of the exceptions:

beige, caffeine, eight, either, feisty, foreign, freight, heifer, heist, leisure, neither, seize, sheik, species, veil, weird

Many people have tried to extend the I before E rule with various caveats and qualifications, eventually reaching the height of absurdity above. There's a spirited defence of the English-style I before E rule here, but I think it is informative that although the author gives no fewer than twenty exceptions to the extended rule, he only gives six words that follow the rule:

relieve, belief, irretrievable; receive, deceit, inconceivable

Despite all the caveats, there are exceptions to all the extended rules, which leads me to the conclusion that the rule simply is no good as a general purpose mnemonic.