Here is an extremely rare Emerson Specwar Knife made under contract for NASA for use on the ISS. There were 30 of these knives ordered by NASA and they were delivered in 1999. The link to the knife is http://www.emersonknives.com/EK_Govnt_Contracts.html
Now for the cool part. When I emailed Emerson knives, I was told that all of the 30 NASA contract knives had the NASA logo laser engraved on the back of the blade. This knife didn't have any engraving, other than the Emerson logo on it, so I thought that it could have been a counterfeit piece.
Lucky for me that I did more research through Emerson and it turns out that this knife is 1 of 4 prototypes built by Emerson, then sent to New Mexico for evaluation. I don't know if this knife flew on a mission, I tend to doubt it because of the perfect condition of the knife, but it's such a rare piece that is never available to the public.