Secret Webpages

Soon later today, I'm going to try adding a secret page or two to my website.
Really, I only want to do that because there's a certain project I'm working on that is maybe a bit 'obscenely niche' and I would love to share it with the world but I feel like if you want to see me mashing my super niche interests into one project you're gonna have to do a little work to get there :]

Anyways, what kinds of secret pages have you guys put on your pages? Got any fun ones?