If I can only enter one, then I guess I'll go with mean corn guy. Btw, it warms my art to see another armatar contest.
Delicious pun.
Multiple entries are fine. :)
How often will you be putting up submissions?
Was planning on pestering Ferret about adding some every 5-10 or so, depending on entry flow.
And; is there a certain criteria one must pass to be submitted?
We (mainly Ferret and me) must subjectively deem them good enough. No exact criteria, just "looks good".
http://i1246.photobucket.com/albums/gg606/Salvidian/thanksgiving.png This one's not quite there (but only took Salvidian 2 mins, so hopefully he's not shocked).

Not sure about this one - it looks fine as it is, but I worry it won't scale down well due to being pixel art-esque. Haven't checked, though.
Gonna be a day or two before I round the first batch up.
(Btw, forum posts display armatars as 70x70, comments use 25x25 and profiles 80x80.)