I'm afraid of my old Lego collection. That was THE TOY my parents used to buy for my brother and I (we got into video games very late in childhood) and there's a ridiculous collection of stuff at my folks house. On multiple occasions, we built a town large enough to cover the floor area of a very large room, comeplete with railways, monorails, and a seaport. Shit was nuts.
I didn't think much of it until a few years ago when a friend who's obsessed with the Napoleonic era asked me ifI had any of the old Pirate legos. I said yes and he asked me if I'd sell any - he wanted to make a reproduction in lego of the entire Peninsular war (!).
Curious, I looked up the prices for some of the rarer and larger sets my brother and I had and realized that a collector would probably pay over ten grand - maybe a lot more - for what's lurking in my parent's house.
Anyway, we'd planned to save to for my kids, or even my brother's kids*, but the way
that's going who knows what'll happen to that stuff.
*
Doubly so, now that the mainstream lego sets they sell are pretty crappy - adult hobbyists who want more accurate or complete models just buy parts online and make their own.