This chap in the US was lucky enough to spot and photograph a Tiger Swallowtail gynandromorph in his garden. This half-male half-female occurrences are extremely rare in the wild, and are highly sought-after by collectors. At the Penang Butterfly Farm's display area, there are two, featuring a Rajah Brooke's Birdwing and Archduke gynandromorphs. As the male and females of these two species are physically very different, it's always amazing to view them.
However, to have shot a live gynandromorph without killing it must be comparable to golf's hole-in-one for a nature photographer.