The new version of Picasa Web Albums added a simple game called "Where in the World". Your mission is to find the correct location for some photos that are already geolocated. To find the game, go to the Explore section and click on "Start Game".
Inspired by Flickr, Google created a new section that displays features photos, recent photos, popular tags and locations.
(As you can see, the screenshots show Google Chrome, which has been released less than an hour ago. The browser is promoted on Google's homepage and you can install it at google.com/chrome, but only if you use Windows XP or Vista. It has a very simple interface and it's incredibly fast.)