A lot of laptops these days will allow you to connect an external display (be it a television or a standard monitor) and use that in addition to the laptop display. This is fantastic when you need to work at higher resolutions and/or more generous screen sizes – very handy when you need to do some more serious work or if you want to improve your gaming or content consumption experiences.
What you might not realise is that you might also be able to output to two external displays simultaneously. If your laptop sports two display output ports (VGA, DVI, HDMI, DisplayPort, etc) then you can try plugging in another display using an alternative port. Otherwise, you might be able to do the same thing with a laptop dock if you have one for your specific laptop model.
However, the potential downside of doing this is that this will probably disable the laptop display. This may not be a downside if you end up with two larger, higher resolution displays but if you’re after three simultaneous displays this won’t work unless your laptop is designed to do so like those with nVidia Optimus functionality.