A very long time ago, I worked for Seymour Cray. He received a surprising amount of crank mail (and back then, it was real postal mail, not e-mail). His secretary filtered out the crank mail, spared him from it, and was good enough to pass the best stuff on to some of the engineers that would appreciate it.

I still have some of it, including a long treatise from an inmate at the county jail who had a theory of interplanetary transportation involving kangaroos whose energy output would be measured in "gigahops".

EDIT: two minor typos