I'd like to share some of the stuff I've been working on. I've been working alot on shadows with Ogre's terrain component. Lately I've been working on an effect known as "contact hardening shadows".
Here is a photo of the effect I'm aiming to reproduce:

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Notice how the shadow has a hard edge at the base of the tree, and as the shadow gets further from the tree the shadow gets softer? That's known as "contact hardening" shadows.
And this is a screenshot of the effect in my Ogre based engine:

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Here's the effect on a vehicle:

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In this shot, you can see that the vehicle, being airborne and quite far above the ground, has quite a soft shadow:

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As the vehicle comes in for a landing, the shadow edges become more distinct, giving the observer important visual cues about the vehicle's relationship to the ground:

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If you'd like to take the demo for a spin, I've made it available here:
https://docs.google.com/open?id=0B3So90 ... zlDT0U4Vkk (23MB windows download)
The demo requires Windows with DirectX 9, and a GPU with pixelshader 3.0. I think it should run pretty decently on even a fairly old GPU (say 2 or 3 years old). I'm running it on an old GTX 260 and getting close to 60 fps.
If you do try it, I would love to hear what kind of framerate you are getting (and with what CPU/GPU). And if you have trouble downloading, installing or running it I would like to hear about that as well.
Thanks for reading!
Chris
[edit: images were too big to direct link, so created smaller thumbnails and added links to full size 1600x1200 images]