Getting kids excited about science can be quite a challenging task. I have been in the business of getting kids excited about science and electronics for several years now, and we have found the best way to inspire is to show them things that they could actually do (and understand) themselves. Our approach has been to be as thorough as possible as possible in explaining what happens in our projects, while still leaving some room for independent thought and creative thoughts. Striking that fine balance is key. The DIY community on the internet can be a great resource. My suggestion is to just point them at websites and give them credit for "expanding" on any project they find. Make sure you don't just give them credit for copying a project, they have to add something of their own. We have some ideas on our website which tkjtkj mentioned above (mostly microcontroller based) at http://www.nerdkits.com/videos/. A good friend of ours has more mechanical based projects at http://www.crazybuilders.com./ The Make blogs and Sparkfun have some good stuff too, but it tends to be a bit too advanced for the true beginner.