Ubuntu. Repositories.

Skype Repo (via canonical):
Run:
$ add-apt-repository 'deb http://archive.canonical.com/ raring partner'

Google Repo:
1. Add key. Run:
sudo wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
2. Add repo for Chrome:
$ add-apt-repository 'deb http://dl.google.com/linux/chrome/deb/ stable main'

Dropbox Repo:
Run
1. Key:
sudo apt-key adv --keyserver pgp.mit.edu --recv-keys 5044912E
2. Repo
$ add-apt-repository 'deb http://linux.dropbox.com/ubuntu raring main '




Update package base:
$ apt-update