How to Install VirtualBox 4.0.2 on Ubuntu 10.10: A maintenance release of VirtualBox 4.0 is already out now. The latest version offers major new features such as redesigned user interface, new display mode, support for more than 1.5GB of guest RAM on 32-bit hosts, support for new virtual hardware, and more. Meanwhile, this maintenance release fixed several issues and polished a good number of existing features.

Here is how I installed VirtualBox 4.0.2 on my Ubuntu 10.10 (Maverick Meerkat) desktop:
1. Edit /etc/apt/sources.list file using GEdit:
$ gksudo gedit /etc/apt/sources.list
2. Add the following line, and then save and exit:
$ deb http://download.virtualbox.org/virtualbox/debian maverick contrib
3. Add gpg key:
$ wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
4. Update the source list:
$ sudo apt-get update
5. Finally, install VirtualBox 4.0.2:
$ sudo apt-get install virtualbox-4.0