Last weekend while making apple cider with about 30 people, I tried to convince them to not break open the apple seeds because they contain arsenic. Several people were in denial about this. So many that I started to doubt myself. So I googled for it and found a lot of useful information - including a page on how to commit suicide via apple seeds (it takes about a half cup of seeds, just to be sure).
But more interesting were some pages that were loaded to the gills with interesting trivia bits.
"A litre of vinegar is heavier in winter than in summer." Why is that?
Vinegar is mostly water, and water contracts as it gets colder until it gets close to freezing, at which point it begins to expand again. (Vinegar freezes at lower tempertures than pure water.) Liter is unit of volume, so a cold liter of vinegar simply has more vinegar than a warm liter does.
I'm generally suspicious of lists likes these. I've received a few via e-mail that mix bizarre-but-true factlets, with bizarre-and-partially-true and bizarre-and-totally-ridiculously-false ones. It can be hard to distinguish.