Google PR has been updated recently, how about your sites. For me it seem bad, most of them are downed...
HA... HA... let it be! 
my studyPark was 0 on PageRank now it got 2. I'm happy!
When I search for PR of any of my sites, it shows Unknown 
My site still have pr 2 but some more of the pages now has pr 2 as well. I haven't worked very hard with getting links recently so I'm couldn't expect anything better.
My 3 new sites get PR3 from last update
No PR changes on my old sites
Does Google changes pageranking to all the sites in its database at the same time?!.
There are updates that take place once in a while... and the millions sites of are updated as possible (I don't know for sure, but it takes more than a week between I read about the PR update in forum threads and when my site's pr is updated)
Last time my PR dropped from 3 to 2. At this moment mypagerank.net appers to be offline and I'll try something else to check my pr. I'll be back later with updates 
I have not found any changes in my website statics.
yes i went a few days ago to check my page rank and i also got unknown! hopefully this will come back eventually... 
this is sick, i got my PR reduced from 4 to 2...
also google is banning most techniques of bots checking your site PR, the best way to see the PR is install the google toolbar
I got a PR 3 for my blog, TeenBlogger.net.
Hehe. 