I signed up last night to help to index the 1940 Census!
Although I'm not in it, my parents and grandparents are!
I've started with doing a few marriage licenses [indexing for Kentucky]. And my preference is for an intermediate difficulty. That means there some real "hum-dinger" handwriting going on! But you can choose to simply index those records with a better handwriting, which helps if you have difficulty interpreting some pretty sloppy writing!
Have you signed up yet? If not, head on over to the project site and sign up!