The Great Turtle Race is a fabulous site highlighting conservation efforts with Leatherback Turtles in the Pacific.
I love the way that what could be a dry boring site about marine animals is turned into an exciting race (well, hopefully it will be exciting by Day 14).
The Wildfowl and Wetlands Trust ran something similar (although not quite a race) where you could track the location of Brent Geese as they migrated to and from Canada and Strangford Lough in Northern Ireland. IIRC it hit the headlines because one of the geese ended up in a local hunter’s freezer near Baffin Island.
(Hat-tip to Bob Piper)