Googling from your comment led to M-Discs, which are available in dvd or blu ray, up to 100gb discs. That looks extremely useful.
yeah those are the ones I'm referring to -- if you're archiving something like family history or data that needs to be good for centuries (without having to re-copy and juggle), those are a better choice than just about anything else.
Alternatively, tell people that they can't store something and you're likely to find it robustly mirrored by many.