Here is a guide to install Gnome-Pie 0.4 on Ubuntu 11.10. You can install Gnome-Pie using the Simon Schneegans PPA for Gnome-Pie.
To install Gnome-Pie open a terminal window (Ctrl+Alt+T) and copy+paste the following lines:
sudo add-apt-repository ppa:simonschneegans/testing
sudo apt-get update
sudo apt-get install gnome-pie
To start Gnome-Pie press the SuperKey and type: gnome pie
To start GNOME Pie on startup enable the Startup on Login option.
Gnome-Pie is a circular application launcher for Linux. It is made of several pies, each consisting of multiple slices. The user presses a key stroke which opens the desired pie. By activating one of its slices, applications may be launched, key presses may be simulated or files can be opened.
Gnome-Pie Homepage
Gnome-Pie 0.4 release note