I have had students do this assignment in various classes the past four years, and students really seem to enjoy it. I figure, if I'm going to make them write something, it may as well be something that's seen by more eyes than my own, and maybe do some good educating the general public.

Organismal classes are especially easy to do this kind of thing in, and students seem to take more pride in their work knowing that this is "outward facing." Wiki Education is looking to expand, and are more than willing to help.