Lightning Strikes in the Midwestern States over the Last 2 Hours
Lightning Map Courtesy of Blitzortung.org hobbyist lightning detection network.
Data supplied by Blitzortung network members using their home-built Blitzortung hardware.
The Blitzortung networks members build (from kit parts) the detector which monitors H-field (and now can do E-field) emissions from lightning strikes, and has a set of servers in Europe to correlate the Time-Of-Arrival at detectors v.s. GPS-time and uses that to locate strikes. There is a great (and somewhat hypnotic) realtime map for North America where you can see real-time strike info, and which stations participated in the location of that strike. There is a companion site that offers the same data and uses a zoomable Google Map for display.
For those interested in more information about Blitzortung, there is a Blitzortung forum in the US at WXForum.net.