I'm leaning towards the user clicking something in an email along with phranque now. Maybe a Google Gadget.
It looks like Google Desktop is requesting your favicon to show along with maybe some widget results or something, but producing a bunk link.
I'd just wait a day or two and see if I can find it again. I can't think of anything malicious that could come of it. I think worst case scenario there's a bug in an email/RSS-feed you're sending out (but then why doesn't it happen more often?) or a bug in someone's gadget.