Kinda interesting. In both the July 2006 issues of Popular Mechanics (page 26) and Popular Science (pages 50 & 84) both make mentions about plugging in your Prius. The intesting part is that they aren't talking about the same company. Popular Mechanics talks about EDrive's version which adds 50 miles, will void your warranty (the original batteries are removed and replaced with Lithium-Ion) and cost $12,000. Popular Science talks about CalCar's version, which adds 10 miles (and a bunch of lead-acid electric-bike batteries to your trunk) at a cost of about $3,000. If I had my choice (and the money) I'd go with the former.