I was looking for some info on ballooning weather conditions when I stumbled across this site.
It is a hot air balloon simulator. Very realistically done and very simple to use.
Click on the basket to burn, on the ceiling of the envelope to cool. Drop a marker at the yellow flag and return to base.
At different heights the winds change and you have a small weather balloon to release to guage the winds. It's actualy quite tough, but theraputic.