For laptops running Ubuntu, you can set the action to be taken when the lid is closed. You can choose to keep the computer on, keep the computer with the screen blanked, suspend (kind of like hibernate, but it draws more power), or hibernate (which draws the least amount of power). You can further adjust these settings so that you can specify what happens if the laptop is plugged in versus when it is not plugged in.

To edit these settings right click on your batter icon and select Preferences. You can then choose either the On AC Power tab or the On Battery Power tab depending on which behavior you want to set. You'll probably want to set one, then the other. Once you select a tab go down to the setting called When laptop lid is closed and choose the option you want.

Save your changes when done and now you'll get the behavior you want when you close the lid of your Ubuntu laptop