Growing up, I had one of those slot car racing tracking. And you could run it at night, cause part of the tracks would "glow in the dark" - and so would the cars. Cool....
But the odd thing my dad noticed, is it would glow even without being exposed to light. Yep - it was radioactive, and with some kind of florescent plastic material mix in with it.
So I found this video funny. In the way of "what was old is new again" - someone on ebay is selling "Tritium illumination keychain flashlights". If I understand correctly, they are more "glow in the dark key fobs" But the pic looks way brighter then anything I remember from my youth.

Anways, of the little I know about radiation, Tritium only spits out alpha particles - harmless electrons? No?
Anyways, here's the video - guy thinks he's getting 1 watt out of it. LOL - silly youtubers.