http://www.theblackvault.com/
For something to play around with . . .
Amateur sleuth John Greenwald released over one hundred thousand documents from Projects Blue Book, Sign, and Grudge to the Internet. He requested them under the Freedom of Information Act for over twenty years. They are searchable by year or subject.
More below the glowing orange swamp gas.
Project Blue Book started in June of 1947, and was intended to quell public unease over the rash of unidentified flying object (UFO) sightings in the aftermath of World War II. It received support at the highest levels of the US Government, and was eventually exposed by a handful of Wright-Patterson Air Force Base employees. The project wound up in 1969. Greenwald notes that other agencies also conducted UFO investigations, notably the Defense Intelligence Agency and the Central Intelligence Agency.
The Air Force investigated 12,618 UFO sightings; over 700 remain unexplained (mostly due to lack of evidence).
There are many documents related to Blue Book which have not yet been declassified; Greenwald received a cache of documents from the National Security Agency that were so redacted they were unreadable. He says he will continue to request documents.