Blatantly stolen from Plumkrazee who posted this on OldOldLady's blog:
meme n (mëm):
A unit of cultural information, such as a cultural practice or idea, that is transmitted verbally or by repeated action from one mind to another.
From the Greek mimëma, something imitated, from mimeisthai, to imitate.
And there was me thinking it was a play on 'Me! Me!'