Baby Toolkit: A Year's Worth of Fun: Giving Kids' Magazines

Baby Toolkit: A Year's Worth of Fun: Giving Kids' Magazines
Depending on the kid and the parents, for about the 12+ crowd, another great set would be F&SF, Analogue, Asimov's, Ellery Quinn's Mystery Magazine, Interzone, etc.

This is one where you'd have to be sure to check with the parents first, since they don't have the same level of content filtering that the ones aimed primarily at kids, though I've reread some of the things I read at 12, and I glossed over the bits that might worry parents.

I for one, wish I had known these magazines existed at that age. The fantasy and SF magazines still have a real sense of wonder about their stories that make them a joy for kids and adults.