I am in a very similar situation as I too have been admitted to an Applied Math PhD program at a school of good repute. I have worked as a trader in Chicago for 4 years and at the moment I hold a 'quant' like position until school begins in the fall. Independent of what some popular books may say, the current demand in Chicago for a PhD certified quant is quite large. Furthermore, the potential income is orders of magnitude larger than what you would earn applying your PhD elsewhere. I think if you find it interesting, do it. The beauty of mathematics is that we take the same ideas and apply them to any field we like WLOG. Drop me a line if you wish to talk about this further....

There is a group called The INSPIRE Project (http://www.theinspireproject.org) that, among other things, makes kits specifically for high school students that enables them to listen to atmospheric phenomena. The kits, actually called VLF Receiver Kits, can be ordered either assembled or not yet assembled. If the kids are to be the ones to put the kits together, you have just tricked them into performing some very basic electrical engineering in addition to learning about what goes on in the Earth's atmosphere. As a board member of INSPIRE, feel free to email the site with any questions, and spread the word!