Download site

Hello, I am in need of a Download System script, or a CMS with such plug-in/module.
The main idea is to have an easy to use Download portal, where users would be able to upload and download files. However, I do not need a file manager but a download system which would provide a brief description on each download, and would allow creation of categories. In addition to that I was thinking about adding some sort of points system, where users would be rewarded for their uploads and could spend points on downloading files. This would not have any commercial application but would merely serve as a measure for user contribution.
All in all, I would prefer a rather simple and easy to use solution to some more advanced, feature rich one since this site will be mostly used for a limited and rather private purpose. I had it in mind for members to share their own work and such.
Thank you in advance.

There are plenty of open source CMS tools out there. You might have to cobble together a download interface, either custom or using another script. Do you have a language preference (eg, PHP) ?