Just Cause 2
Just Cause 2 is a sequel (surprise!) to Just Cause. With a bigger map and even more insane action then the first one.
Just Cause 2 is a sandbox game set on a giant tropical island with lots of little islands, it would take you an hour to drive across the entire map and quite a few minutes to fly it.
The game does not take itself seriously and allows you to just have fun pulling off crazy insane stunts. To help you in this endeavour you have a grappling hook, instant deploy parachute and the ability to hijack any vehicle at any time. To top it all off you can get out and 'surf' on any vehicle that you are currently driving/flying.
This game has its share of frustrations that make it less than perfect, but the crazy mayhem that you will get up to goes a long way to make up for it. :-)
There is a storyline, but I just spent all my time blowing things up and clearing out the gangs from the local area in a bid to become lord and ruler of the island. :-)
Overall:
There is always something to explore and see. Love all the little nuances that the map has.