Here is a simple quick reference radar map with a stormtrack toggle to see where storms cells currently exist. If you're looking for more weather maps and detail be sure to check out WeatherBonk or Weathermole.
Active Forest Fire Mapper - This hot Google Maps mashup created by Fire researchers at the University of California, Berkeley, displays current forest fires in the US and Canada. It mashes up with data from the USDA Fire Service and the Center for Fire Research at the University of California, Berkeley. Red squares display active fires, while yellow indicate previously burned areas within 3-7 days. More info here. [Via All Points Blog]