Independent games are fertile ground for marketers and advertisers. Yet distribution channels are limited for existing games. Often, the game was born of a hobby or personal project, and the creator doesn't have the means or knowledge to get his game into traditional distribution vectors. These games, many of which are incredibly novel and make up for the lack of production value with ingenuity, are begging for sponsorship. For marketers and advertisers looking to create a branded game, these same developers are untapped talent.
There are problems with this approach; the infrastructure that developers specializing in game ads and advergames have built up doesn't exist for independent gamers. The relationship and guidelines need to be forged from scratch, but I still believe soliciting independent developers to be worth considering as an option. I would offer up a link to one of my favorite examples of independent game design at Orisinal. The simple but elegant design knocked me off my feet, along with several games I consider to be among the best casual games out there. Independent developers and games won't always be the right choice, but depending on the situation, they may just end up being a very good one.