Ask HN: Simple Apps

I have been coming across a range of simple apps on HN (though comments or otherwise, such as http://untodos.com/ and http://news.ycombinator.com/item?id=646277) and have been wondering, any such simple apps that fellow hackers have found a need for and not had the time or inclination to write? The main directive here would be simplicity, and that the app (or tool) performs one function, and one function only. I have been looking around for a project and if not me, I am sure other can find some inspiration for projects, and others might get value out them. Any thoughts?