Those of you old enough to have learnt some formal grammar and etymology at school (or interested enough to read it for yourself) will know that "children" is an example of a double plural: the old English was childer or cildra, then given a second plural en ending (as in German today). (Also "kine": ky meant cows in archaic English, and kyen is another one.)
Cattle preparing to form a bovine pyramid
But today I saw a new - and pretty odd - double plural today - inelegantly combining an ignorance of a very common Latin word, and of punctuation, in a single word!
"The credit crunch has meant rates, products and criteria’s are changing on a daily basis".
Cringe. I shan't name the guilty party, as it's someone connected with work...
SeasideMan
Pro 
) too.
The last time I was in America on work, about 6 years ago, I saw a newspaper headline that said:
"The Bears have had their winningest season ever"
Last week I saw the word "winningest" used by a UK blogger.
These Americanisms are on their way over here.
"criteria's" is shudderingly bad though.
Cheers, Tom.