Google now has a gallery of more than 1220 Google Universal Gadgets, which contains minimal code that function as dynamic applications when installed on a website or blog, with a variety of abilities. Among the functionality of the gadgets include check weather, get news headlines, play games, miniature look-up for Google Maps or Google Calendar, search tool for Wikipedia or Dictionary.com, download smileys, translate with Babelfish and etc.
To embed or add Google Gadgets to your website or blog, search for the gadgets you want at Google Homepage Content Directory (discontinued). Then click on “Add to your webpage”, and customize gadget’s width, height, border, title and other related options. When done, click on Get Code to locate the HTML source script to insert into your blog or website.
Update: Google Gadgets are mostly depreciated as most services that it can be deployed are either discontinued or dropped the support to Google Gadgets.