Share your bookmarks
I've been following an RSS feed of bookmarks from somebody for years. I don't know where it came from or anything about the person, but it's an interesting almost StumbleUpon-like feed. I wanted to make one. So I made a tiny "spec" for bookmarks just to do it and included a few utilities with it, like outputting the list as gemtext or as an RSS feed.
I integrated this into my website and gave it it's own page and RSS feed. Took an hour or so and now I can have a subscribable dumping ground of cool stuff. Neat, I love the simplicity of computers.