Gingerbread and Candy Corn (
http://gingerbread-and-candy-corn.appspot.com) - A one-stop spot for finding houses with holiday decorations. Sadly, I don't think it'll be ready for Halloween :( Though it should be ready for a launch near Black Friday :)
As a kid, I always loved driving around looking at Halloween/Christmas lights and as I've gotten older and moved to a bigger city, its been a little difficult knowing where to go to see good houses. The only real way to do it right now is YouTube videos or hoping your local newspaper has it covered.
The reason I think its cool is I'm learning to use Google App Engine on a responsive HTML5 style page. Since I'm not too graphic oriented, I'm learning how to use Flat UI to my advantage (as you can see in the nowhere near done demo). I'm going to get to learn a lot of web hosting stuff, like the official webpage currently is hosted with Dreamhost, but how do I get GAE to play nice with that, managing/handling requests, how to appropriately display houses without killing my GAE free package. If it generates enough success this Christmas, I'm hoping to spend next year learning mobile development for an app that does the same thing, but also gives you directions.