Bookeen just announced a new contest, send a photo of your cybook and you might win one of their new covers available on their site. They're going to give away one cover each week during the mont of June. The photos will be posted on facebook ; either you can post it directly on their facebook page, or you can send it by email to community(at)bookeen.com (you don't have to have a facebook account).
All the details are on their blog :
http://bookeen.com/blog/win-your-cover/