Here's Microsoft's explanation of the pack: "With the Windows Experience Pack, you are able create an alter-ego of yourself in a specific destination – a beach, mountain, safari, or city. When you create your alter-ego, you create a fully customized avatar for that destination that becomes a part of a Windows Live Messenger and Windows 7 theme for your PC. You’ll also be able to download a .jpg image of your avatar to share, print, or use as your icon on social network".
Here's our explanation of Microsoft's explanation: "You can put your face on a cartoon character. You can then download that picture. That's pretty much it".
But wait - that's not quite it. Beyond the "1 static display picture" that we discussed, you also get "4 dynamic display pictures", a "wink", 7 "new emoticons" and a "new messenger scene". Best of all, if you've got Windows 7, you also get either 3 desktop backgrounds or a screensaver featuring multiple photos. Not both, you understand. Microsoft isn't made of money, y'know.
If for some reason you want to do this, you can go to Microsoft's far-too-snazzy website for the offering and there you'll be talked through the process. The company warns, though, that it's optimized for Windows 7, so if you're on Vista or XP then "performance and features may vary".