Flash Powder?
Well, it was over 20 years ago - but I got some magnesium wire to ignite a thermite reaction when I first read about it in HS. I do see that it’s not as open-and-shut an ignition method as I thought, but it may work.
I am actually a little concerned about giving away potentially dangerous combinations on the internet. Ive checked, and actually the search terms that have been provided are not quite enough to get it. To be quite honest, it’s probably not that big a deal except it was like finding out that Kevlar could be destroyed with a tissue bullet. (Thats as much of a hint as I’m giving.) Really though, its not that big a deal.
Sandwich them between two sheets of glass, and you’ve got insulating windows, with greater thermal resistance than most walls. Okay, they’re milky-grey looking, so you don’t put them in where you want a view, but they’ll make amazing skylights. 
Yeah—I got my little cousin a spinthariscope there, last year.
And I’ve always wanted to get some trinitite, either framed for my wall, or to try and make a bullet out of it—I have a theory about the potential anti-supernatural properties of such ammunition (That reminds me…can I still get DDT anywhere legally in the US?)
Come on! We’re fighting ignorance here! This is the Dope! Tell us what you can do with Magnesium powder.
After checking out Wikipedia, it seems to say that Mg is really rough because if you try to put it out with water, it will only get worse, as it will start producing hydrogen. Is this what you’re talking about?
Actually, I just realized that I learned about this formulation from wikipedia, so if you search around using the various terms that this post has mentioned you can find it yourself. It’s just that it’s something that I never would have guess reacted with anything.
I can’t be blamed for something you learned from a public source. 
Be warned though, the products could be toxic.
When I was a kid, we would beg our parents to take the somewhat out-of-the-way route to the relatives’ house so we could stop at Edmund Scientific (mentioned upthread). Tiny mirrors! Tiny bioluminescent stickers! Mercury! It was terribly exciting even from a non-scientific perspective.