Every two years, the National Alternative Fuels Training Consortium (NAFTC) runs a series of events called National AFV Day Odyssey (the AFV stands for alternative fuel vehicles). The 2008 date for the day is, well, today and the idea is to coordinate support for the alternative fuel vehicle industry. Different sites will host ride-and-drives, vehicle displays, Q&A sessions and workshops. Another side of AFV Day is to get better communication going between the people in the USDOE/Clean Cities Program and others.
If you're looking for an event to attend today, you can check out this list for details of where, but in the event listings that I looked at, exactly what and when wasn't specified. Maybe the system will be a little more clear in 2010. Thanks to Greg B. for the tip.
[Source: National AFV Day]