If you have already tried out most of the GPS applications out there and now there's nothing to do, try out this GPS game , 'GPS Mission'. Although I installed, haven't tried it out yet. This image gives the details of playing the game:
(click image to zoom)
Would surely create a mission once I am a lil free. Just thought that more the number of people have the game more interesting it would be to play it. I think its worth trying. Also they reward the best mission with an N82 at the end of each month which makes it more worth trying it ;)