Wow...I thought you must be exaggerating, went to the site...and could not tell from it just what the heck POTA is. I could guess because I had heard previously of SOTA (Summits on the Air) and POTA is like SOTA but in parks instead of on summits.
This site [1] gives a better idea of the basics.
Here's an article on SOTA [2].
[1] http://www.hamparks.org/
[2] http://www.arrl.org/radio-operating-from-summits