Today is the last day to enter the Radio Shack sweepstakes to win a new Nissan Leaf plug-in all electric car. It’s the big prize in Radio Shack’s Earth Week celebration, ending April 23rd. You can enter online, no purchase necessary. Or, if you bring in your old electronics to a Radio Shack store for recycling, you can get enter the contest and also get an additional $10 off any new mobile phone purchase. The Nissan Leaf has just been declared 2011 World Car of the Year at the New York Auto Show, now open to the public at the Javits Convention Center.