Atari's E.T. (quite possible the worst game ever made) actually outsold the Atari's most popular game, Space Invaders, by half a million copies.
I swear I saw/heard that fact somewhere not long ago.
Do you have a source? It's driving me crazy.
The Atari Pacman outsold both E.T. and Space Invaders Combined. Also, according to Wikipedia, Space Invaders out sold E.T.
Wikipedia Entry
I had also heard about E.T. outselling Space Invaders (hence why I brought it up).
While Wikipedia says (as Nyu posted) that Space Invaders outsold E.T., other accounts describe it the other way around.
It's hard to find a credible source for this one it seems.