Install a bat house. Plans via pdf free dowload included. (The UN has declared 2011-2012 the international year of the bat and encourages people to get involved. Their numbers have dwindled from white nose blight. Their importance to the any ecology is often unknown. In short, they'll clear your garden of bugs in one night if they're around. :D)
A lesser long-nosed bat pollinates a cross section of a saguaro cactus flower. Photo by Merlin D. Tuttle, Bat Conservation International.
From fickr - part of www.batconservation.org. This is a dog-faced fruit bat. ("I was given the rare and fascinating experience of stepping into some of the bat cages at Cranbrook Institute of Science in Bloomfield Hills, Michigan. Just me, my camera, and 160 live bats.")