I decided to make a CAPTCHA plugin for Trac called TracRecaptchaPlugin, to stop spammers using the ticket system. There is an existing Trac plugin to fight spammers, but it still lets through many automated spammers.
The plugin uses the reCAPTCHA service and is serving me well so far. Here’s how it looks within the template:
This is my first publicly released Trac plugin so I’m unsure how it’ll perform out there, so feedback is welcome.