Workrave is a free software application intended to prevent computer users from developing or aggravating occupational diseases such as carpal tunnel syndrome and repetitive strain injuries. The program frequently alerts you to take micro-pauses while an anime character walks the user through various stretching exercises and urges them to take a coffee break.
Download: Workrave 1.10.1 | 13.6 MB (Open Source)
Link: Workrave Home Page