http://www.boingboing.net/2010/12/19/yelping-at-saints.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+boingboing/iBag+(Boing+Boing)
We don't have any sun today, so I haven't been able to try it, but I'm sure a halo will be there, when I do.