Sporkie is a challenge/response spam email filter.
It works in the same manner as the ASK project, except that Sporkie uses CAPTCHAs. The main advantage to using CAPTCHAs is that it catches automated spam bots that don't spoof their email address. With ASK, such bots would get through the system.
This software works by sending a verifcation e-mail with a link back to anyone who sends you an e-mail. The user must then follow the link and enter the numbers they see in an image. If they input the correct numbers their e-mail gets put on a white list. All past (e-mail sent within the past 90 days) and future e-mails from that user will go directly to the intended account. It will completely eliminate all spam since it verifies that the e-mail address the mail was sent from was the real address, and that a human person uses that e-mail address. Other systems simply verify the address is a real e-mail address.
Sporkie is written completly in Java. It requires Java 5.0 or higher, however very minimal portions of code use 1.5 specific idioms. It would not be hard to write a Java 1.4 port.
Sporkie is provided under the OSCL Type-C license.
Sporkie is currently in an alpha stage so there is no stable release as of yet.