Zend Developer Zone: "Drizzle is a new, lightweight fork of MySQL specifically designed for cloud applications. Although Drizzle is still under development, it's attracting a lot of attention from developers around the world. This article introduces you to Drizzle and shows you how to use the Drizzle PHP extension to perform queries, retrieve result sets and handle errors in your Drizzle+PHP application."
There's been a lot of buzz about Drizzle lately. Need to check that out some time.