The Powell Glider. Sort of.
This is my first add-on attempt. I didn't bother to add RCS thrusters (as far as the actual showing of thrusters, at least) - mostly, this was an exercise in learning the ins and outs of Spacecraft3.dll, as well as dealing with textures, etc.
It flies like a brick on the way up, and handles like a piece of paper moving at high speeds on the way down - but it's certainly able to be handled with careful control.
I'm honestly not sure if it's able to be landed within "realistic" parameters, but it's fun to fly - it's been out as far as Neptune and back.
Enjoy the mod!
-Eppy
Note: This would be considered a "high-resolution" mesh. This probably won't run that well on lower-end computers.