Microsoft unexpectedly released an update to the Zune PC software and device firmware today, bringing both up to version 3.1. Here’s the news from the Zune Insider blog:

The team has been doing a little extra work heading into the holiday season; in fact this week is a busy one. You are going to see some pretty cool things coming for Zune that we thinks you'll enjoy.

Starting today, Zune gets a little update which will bring a handful of free games, a refresh to Zune Social and incremental improvements to the software.

On the games front, we are giving away three new additions, Checkers, Sudoku and Space Battle, plus a new multiplayer mode and single player difficulty levels for Texas Hold’em.

The team also did some great work the Zune Social visual refresh to make it easier to navigate, as well as adding a new feature called “like minded listeners,” which will let you see how compatible your music tastes are with other listeners and friends.

On the more techie side we focused on improving overall stability and performance in the Zune PC software and device firmware, such as improved play count reporting and content synchronization between the Zune software and the Zune device.

To get the new update, use the PC software, just click settings: check for updates.

Here are some shots from the update process…

Thanks to Jeremy M. for the heads-up.