I was going through all of my LEGO sets the other day and had a few pieces that didn't go anywhere. I was able to identify most of them using the instruction .PDFs on LEGOs site. Actually found out I had a SW Landspeeder, the one with the old school jet engine pieces. :)
I have one of the brown 2 piece "rocks" that has a yellow-green crystal in it, and I can't find the set it came from! None of the sets I looked at jogged my memory. Maybe the set is older than what they have scanned? I know it was from around 2000 and was a small set. I looked at all of the miners sets and nothing rang a bell, and I don't have any other parts to help me out.