Snowbox is a small and easy-to-set-up POP3 server. It supports APOP, SSL, and IPv6.
The plainMail2HTML utility creates and attaches an HTML part to a text/plain email message. It can be used with text-based email clients (e.g. Mutt) to convert a text/plain message into a multipart/alternative with an HTML part and send it.
An online translator with some advanced features.
Map/reduce code for processing Wikipedia Pagecounts.