Invisible Friends (or, A Boy and His Dog, some monkeys, walking fish and a few damn aliens)
by Steven Sawicki
A man meets a group of aliens who want to use his basement as the center of their operations while they study mankind. The only problem is, Earth is pretty far out on the galactic arm and all the competent alien study teams get posted much closer to galactic center. The farther out you are, the farther out you will be. There's monkeys, Elvis, a dog who drives, and lots of insight on humanity.