Convuser: This is the very first perl program I ever wrote. It's quite handy though, and I still use use it every once in a while. It basically lets you enter in a list of names and passwords in a text box, and then it encrypts them into the Base64 .htaccess format so you can put them in your .htpasswd file. It's much easier than typing them in one by one. Sample .haccess and .htpasswd files are provided, (rename them accordingly).
Egetter: Egetter queries the MSU database for all email addresses, (starting with aa through zz), and email_parser parses through the resulting files and compiles a list of email addresses. It takes a long time to run, and uses random query intervals so that the DB doesn't get overloaded with queries so other people can't use it.
Killbots: Fills out almost any web form a specified number of times. It works well when a spammer has a fake email address but leaves a web address. Make a copy of it and then edit it to reflect the variables in the form you are submitting to.