Metaculus is running a small competition right now called the Bentham Prize. The premise is simple: contribute to the discussions of questions on Animal Welfare. The best record of contributions (subjectively assessed by human judges) will win.
If you've been waiting for a reason to start practicing forecasting, this seems as good as any. It's gotten off to a slow start (in part because the Metaculus community has become quite distracted by another matter), so the field is wide open!