Примеры самых разных комментариев (в основном - смешных),
http://stackoverflow.com/questions/184618/what-is-the-best-comment-in-source-... (18 страниц текста)
Например:
//
// Dear maintainer:
//
// Once you are done trying to 'optimize' this routine,
// and have realized what a terrible mistake that was,
// please increment the following counter as a warning
// to the next guy:
//
// total_hours_wasted_here = 41
// 
