Now go outside and look at the sky.
I stumbled over this application by accident and was amazed by how much time suddenly just disappeared from my day:
Nasa World Wind is an interactive globe - which doesn't sound to glamorous, until one had a chance to play with the application. It is sheer unimaginable how far modern home PCs and the Internet have come. Here is a program that allows the user to fly across continents with the flick of the mouse, and then to zoom in down to a point where it is possible to recognize the types of vehicles on the roads!
Most of the satellite data is only a few months old, and some add-ons allow to use day-old satellite data. In addition there is huge amounts of scientific data available that can be overlayed and combined with the gorgeous 3D view of our planet.
An absolutely amazing application - for free! It's refreshing to see such a worthwhile and educational project being produced by a federal agency in this day and age of right-wing anti-science fearmongery.