Wikipedia summaries for Greasemonkey
Displays a summary of Wikipedia entries as title of links to Wikipedia.
For example a link to the greasemonkey article will get a title like so:
You can install it from userscripts.org (or directly from this site).
This uses the HTTP interface to my wikipedia summary stuff. The same interface can be used in other ways, there's also an example of how to use it via JavaScript callbacks here - which is interesting as it means you can add it to any web page..
There are two interfaces, raw JSON as used by greasemonkey (example) and JS (example).