Novak Djokovic, the world's third-ranked tennis player, provides voiceover on a new site created by Ars Berlin for racquet brand Head called "Speed Lessons."

Promoting the brand's new Speed racquet, the site is presented in crudely drawn fashion and features a handful of amusing, animated short films such as "The Service" and "The Smash" that highlight the effects of the Speed model. Visitors can also take a quick multiple-choice test and submit their email addresses to win one of ten Head Speed racquets signed by Djokovic. You can also join the Speed Lessons Facebook profile and bookmark the page through iGoogle, Technorati and del.icio.us.