I'm at a friend's place and using her computer. It's less than 6 months old, a Compaq Presario SR1030NX with a Compaq 7550 monitor. The monitor takes on a (usually) reddish cast at random times for about a second, and then goes back to its regular colors.
She called HP/Compaq about it a couple months ago; they send a new monitor, but the problem still continues. I've run all the tests I could think of, degaussed it, etc. etc. -- everyhing said "Hey, it's just fine!"
My thought at this point is that the video card is bad and that she'll therefore have to deal with HP's Bangalore Office again.