I spend a morning a month maintaining a classroom of PCs for an Adult Learning Center. It's no effort for me to do and they love it.

I think the key to volunteering is to control how much time you spend doing it. Don't over commit and get sick of it.

I watched some Mega-Cities series of documentaries from National Geographic and there was one about Paris and it's sewer system. A large part of it was talking about how they were using it to run Fibre throughout the city. I'm pretty sure it was the same US company doing it too, robots and all. It was a fibre/wireless network.