It’s cool that Google have mapped the night sky.
This set me thinking that it might be really nice to create a cellphone app which allows the user to point his mobile device at the ground and see a simulation of whatever part of the world is beneath him (In the same way that fighter pilots can see through the floor of their planes, when wearing the latest helmets).
Scanning this backwards and forwards would show a number of spatially-arrayed labels, located on the outer, transparent surface of a simulated sphere (The onboard cellphone gyro could be used to calculate the required angles).
The labels could be set to show famous landmarks or the hometowns of emigrant relatives etc.