On a daily basis, I check this websites top 20 most retrieved pages. This list contains the usual pages such as the index-page and the random Dilbert page. But, there is a page that I wouldn't expect to be on the list.
And it's the page that you can use to sign in for a account. For some reason there are scripts going around that just keep on trying to add a new account. Some days that particular page is used more than all other pages put together. But using the Approve Membership module, I stopped handing out accounts to people I don't know. An advantage of this module is the changed layout of the page you use to sign up, so most scripts just fail. But there are still people busy harvesting accounts. Weird.
I stopped blocking ip-addresses on a regular basis, but I'm still doing it more than twice a month. Some people never learn.