Josh Marshall links to this a few posts down over at TPM. It's something I've been hoping somebody would pounce on, and a group called Win Back Respect has come through.
It shows the President at a dinner a while back, making jokes about not being able to find WMDs (yeah, that dinner). And then the sister of a soldier lays into him about it.
They're looking for donations to put this ad up. The research on it shows an "unprecedented 8 point swing" from Bush to Kerry in focus groups (yes, take with cube of salt), so it's has the potential to be amazingly effective. Give generously, if you can.
Check out the ad here:
http://www.winbackrespect.org/ads/