Believe it or not, I suck at X configurations. I really do. I don't have the time to study more about X so I took the easy way out.
1. Connect the projector to your laptop.
2. Do this in command line.
3. Just press Enter through every screen.
4. Restart X for the changes to take effect by pressing CTRL + ALT + BACKSPACE.
5. Log in again as you always do.
6. And finally, the projector will automagically display your Ubuntu desktop and you can show off your desktop effects to your co-workers.