Soaring Discussion Forums
Crowd-sourced list of discussions related to soaring.
Comet Program, Mountain Waves and Downslope Winds
Excellent training resource targeted at students of meteorology but easily accessible and understandable for anyone interested in learning more about this topic. Also available here as interactive training program. (The site requires registration but is free to use.) You can also search for other training modules here.
Speed Polar Data for many gliders
Useful resource to look up data on many gliders – often not easy to find.
Glider Test Reports from Dick Johnson
For about 20 years staring in the late 1970s, Dick Johnson wrote excellent test reports of gliders. They are very useful if you consider purchasing a glider from that era.
Idaflieg (in German)
Cooperation between various German gliding clubs to scientifically investigate questions of interest to the soaring community. Some examples include: tow plane performance comparison; speeds in a spin to help improve cockpit safety; glider tests; etc.
Rigging
Rigging can be a pain, but some have it perfected. Here’s a video of Frank Paynter rigging a Discus 2 (I think) in just over 7 minutes without any expensive rigging aids. And here’s Herb Killian rigging an LS8 with a home-built motorized rigger in 9 minutes.