I put a (semi tongue-in-cheek) comment in some billing system code I wrote 8 years or so ago, pointing out a date overflow problem, something like Y292277026596 (can't remember the exact year now, but the comment was accurate). Comment went on to say that if the system was still in use at that time, then I would fix the problem.

I expected to be called out for this comment some day, but never have -- makes me wonder how often people read through code.