Digital camera artifacts? What is this?

[seftonm]

I noticed this pattern in one of my pictures and want to know if it's a common type of artifact (and what is it called if that is the case?) or if there is something strange going on with my camera or technique. The camera is a Canon S3 IS.

http://home.cc.umanitoba.ca/~umsefton/whatsthis.jpg

Original 2.5MB image can be viewed at http://home.cc.umanitoba.ca/~umsefton/IMG_0223.jpg

[goofball]

a bit more info on the picture. Were you shooting through a screen? What was the situation/scene like?

It's not your typical digital artifacting. It's not even bad moire.

[seftonm]

I was shooting something that was relatively brightly lit. No screen or anything. Look at the full image if you want.

[DirtyLude]

That looks like something wrong with the camera. It's like every second line of pixels is unscanned.