blitzortung.org is a worldwide distributed network of several hundred lightning detectors, built and operated by amateur enthusiasts mostly in Europe, Scandinavia and the US. Info from each detector is collected and used to triangulate cloud-to-ground lightning in real time, producing maps of lightning around the globe as it happens. In the first year, my detector recorded about 10 million strikes; others are even more active. There's a considerable waitlist for the mostly-assembled board, which needs outdoor antennas. Information in the forums.