I have a similar situation:
I recently bought a few sites and domain names from someone. A lot of the names don't really have any development value in them for me at the moment, but they came along as part of the package. You know the type of deal.
Anyway. The Toolbar pagerank indicator tells me that one particular (undeveloped) domain (widgets.net) is a PR 7. There's no way this site (it's never been developed, to my knowledge) could legitimately get any PR.
Now I know that toolbar PR means very little indeed, but this is, to me, a very odd thing.
On investigation in a G search for "link:www.widgets.net", I get links to a completely different site - one I have never heard of before, and certainly one I've never had any dealings with ("www.differentwidgets.net"). If I attempt to do any more searching using the quick links that G supplies, it then begins searching for, (e.g.) "site:www.differentwidgets.net".
Any thoughts anyone?