If you're not looking to do something super complicated maybe you can look into Sinatra (ruby). I'm not sure if python has something similar if that's your language of choice.
In addition to web.py (mentioned below), there is also cherrypy. There are a lot of great lightweight frameworks that still give you some of the benefits you get from something robust like rails or django.
Rails and Django make a few more assumptions about what you're going to do (eg creating a directory structure and giving you easy shortcuts to create forms to edit pages) that are pretty useful when you're building a webapp and want to create multiple reusable parts, but may be overkill for a simple HotorNot type page.