There are some, not wide spread reports, of a Google PageRank update at WebmasterWorld and DigitalPoint Forums. Not everyone is agreeing on this, but there are enough people saying their PageRank values in the Google Toolbar has changed.
Some are saying they see gray bars and some are saying their PageRank is up or down a point. The last PageRank update we had was in July 2010, so I believe we are due an update now.
This may be a minor PageRank update and again, minor or not, what you see in the Google Toolbar has zero impact on where you rank in Google.