runtah

I hate the fact that I have to figure this out for every new distro I use. But here it goes for Xubuntu. Tested and working in 14.04 LTS.

1. Open the file /etc/systemd/logind.conf
2. Find the line "HandleLidSwitch="
3. Set it like "HandleLidSwitch=ignore" and if it has a "#" (hash" in front of it, remove it.

Save and reboot and you are good. :)
Credits: http://askubuntu.com/a/362692/145915

In my workplace they have Linux Mint 13 setup for the machines. I personally hate it and my employer too, so we will be shifting to some other Distro very soon, but in the mean time I had to make do with it. We have an extra display attached to every laptop. One of the things that bugs me the most is the "Power management" doesnt have any "Do nothing" option. And if you somehow (yes, theres a way) make it appear, it does the exact same thing as "Blank screen", so yeah, "Aw snap!!". It didnt take much of googling to find Mint forum page that solved the problem though [ http://forum.linuxmint.com/viewtopic.php?t=106532&f=208 ]
Basically the problem is caused by a faulty assumption in design. It always executes and Screen Blank instruction set, when you close the laptop lid. What you have to do is just comment out one line in the event handler script.
1. First open the file, you might need root rights to edit this, so use sudo if you need

/etc/acpi/lid.sh

2. The find the line

. /usr/share/acpi-support/screenblank

3. Comment that line out with

#

It should be fixed immediately.