Question: I want to have something like bitbucket.org or github (but for mercurial!) on my VDS. I don't need full functionality, but I need it being able to serve repositories, accept changes (with auth!) and creating new repos in one-two clicks in web interface. What can I use? Thanks

Answer: 
I have used bitbucket.org but I also wanted an in house DVCM server for my web development team, so we went with Redmine. This is tested and installed easy using BitNami images, <http://bitnami.org/stack/redmine>
For your needs you might want to take a look at [gitblit](http://gitblit.com/)
It is fairly basic and simple. It provides web-UI so you can manage as many repos as you need. However I found out that they don't have per branch permissions out of the box (requires some ground work with groovy scripts). On a flip side if it doesn't bother you, then it might be it!

Cheers mate!