A user a the Ubuntu Forums has compiled a list of interesting and useful terminal commands that can be used in Ubuntu:
Since I’m a noob myself and don’t know much about the inner workings of the terminal, I won’t shed any light on that subject. But, I would like to share some interesting and useful terminal code I’ve found. This code was only tested on Ubuntu Feisty Fawn, but it will also work on most Mac OSX computers and should work on all Ubuntu releases.
Read the list and forum thread here.
Of the list my favorites are: uptime (shows system uptime, my server has 188 days), cal (shows a nicely formatted calendar), and gksudo nautilus (starts a root Nautilus file manager, useful for editing configuration files without the terminal).
I also find these additional commands to be useful: w3m (text based web browser installed by default with Ubuntu), python (python shell useful for doing calculations or writing a quick script), sudo (execute a command as root, safer that switching in and out of root with su), lsusb (view a list of usb devices), and lshal -m (monitor devices in real time, watch it when you plug in or remove usb devices).