I've been sitting on a nice domain name (no specifics...) and it's been a "someday, I'm going to build this simple idea" application.
A few days ago, someone offered to buy the domain. Not for much money, but still, it's a kick in the pants.
I'm going to build that thing. Probably take me a few weeks, it'll scratch the itch, and it might even be useful. I've spent a couple hours fleshing out some user interaction and it looks like it'll be fun.
What else are rainy days for?