http://www.youtube.com/watch?v=IZMZuYr5lDA
http://www.youtube.com/watch?v=KAs53d1kzPU
Two very clear launches into thermal, you can actually see the plane rising. You can also see the instability of the thermal (the video's were taken on a small island close to the Netherlands where it's always pretty windy). Browse youtube for more video's
(yes, Iresurrected this thread because it contains some very useful information!)