Two app that I like lately, for their entertaining potential: It's a bit old but I am still fascinated by this "If I dig a very deep hole, where will I end up?". It's a very basic google map app where you can choose to dig up somewhere and see where you go to arrive on the other side of the Earth:

"Are you concerned about where you go to arrive if you dig a very deep straight infinite hole on Earth? Your problems are solved! Surf on the map below, choose where you will dig your hole and click there. After this, click on "Dig here!" and you will see the place where, one day, you will (believe me) put your feet."

And of course, flickr vision is also compelling. It shows realtime, geolocated Flickr photos on that globe:

Why do I blog this? Those are fascinating and ludic spatial application that I find enjoyable, no more, no less. There are not perfect of course but they reflect some interesting aspects as well as intriguing motivations (following people's photo streams, digging the earth, etc.).