No, I’m a sheep.

Anubis is nice (I want to note, that I liked the former mascot better) but has the problem that users who disabled JS are left out. But there are proposed solutions.
An other tool is go-away, with the same effect but also inclusive for non-JS users.

On an other page I want to add how cool it would be that when the challenge fails, instead of blocking, these tools would redirect to a scraper labyrinth.