Stumbled across this album in which an artist personified some of the more unusual mating habits found in nature across many different species of animals. I found it to be rather informative and pretty well done. My favorite habit depicted in here is that of the Ruff, which is a bird found in the marshlands of northern Eurasia. This bird in particular is interesting as there are three different "types of males" which all mate with females, yet each one takes a slightly different approach.
Here is a picture of one of the females, of which there is only one form.
Hope you enjoy.