It's Earth Day on (some of) TV. Below are some marked programming that is Earth Day-related and of course there's plenty online, including web "TV" properties like Joost who have launched an Earth Day Channel. 8:00pm Nova: Car of the Future PBS/KCET - Tom and Ray Magliozzi of NPR's ``Car Talk'' examine new technologies and ideas for transportation, including alternative fuel sources. Earth Day!......