This is the time where people lose motivation and decide to just go to bed. Remain entertained and occupied. Listen to loud music, drink a cold soda, eat an appple, play a video game. messaging a friend is always a good thing to do when your up late. If you dont have any insomniac friends, you can use Omegle. http://omegle.com/
Watch some TV. Avoid news shows, or documentaries. They are boring and can make you doze off. If you feel yourself falling asleep, lick a finger and rub saliva on your eyelids. this might sound gross but it keeps you from falling asleep. You can drink a cup of coffee, or have an energy drink, but keep in mind, later on most caffinated drinks will make you crash, and you will become drowsy and tired.