I think I kept this video short and informative ;-) it shows what and how to install Virtualbox on Calculate Linux or even Gentoo.
A little preview of what is to come on my quest to compare Calculate Linux with different Distros and about my new Synology Diskstation and all the tools it provides.
To install Virtualbox:
sudo emerge -avq app-emulation/virtualbox app-emulation/virtualbox-extpack-oracle app-emulation/virtualbox-modules app-emulation/virtualbox-additions
sudo usermod -G vboxusers -a username
sudo reboot