I use a small, clear waterproof bag, the type with a multi-fold velcro at the top. After a couple of years it has proven durable and has stayed dry.
I think that the idea of an Altoids tin is great - its a good (and often cheap) way to get people and kids engaged and thinking about equipment, how it can be used and what they would do in particular situations. For some people the exercise may stop there, for others they will naturally start to expand...
I guess that most people on the forum would have "survival" built into everything - key ring, wallet, purse, backpack, car, home, work etc ... but I would hazzard a guess many would have started with some kind of a mini-kit - like an Altoids ?
Altoids - Its like those soft drugs that go on to get people hooked on hard core-survival !