Google has launched a new site called Google New, which is designed to let users see all of the latest offerings from the company. Google launches new products and features (not to mention acquisitions) all the time, so this should be a good place to check up on everything. 

You can sort the offerings by product or area of interest. By default, it shows the latest offerings for any given product. Areas of interest include business, developers, education, entertaiment, geo and maps, mobile, non-profit, and social. 

While not listed as the latest feature, Google Instant is currently the featured offering on the site. 

For any given offering, Google provides what I assume is the original announcement/blog post for each, to give you some background about it.