The things that will wake a baby during the night are mostly hunger and teething.

Does he seem to be in pain or hungry? Make sure he is getting enough to eat during the day....what is his menu like during the day? If it is teeth, a little dose of Tylenol before bed will help with his night time awakenings.

He could also just be in the habit of waking up for no reason. In this case it is important that you do not go in and pick him up but let him get back to sleep on his own.

Here is a link to a sleep schedule that will give you a guideline for getting him on track. Best of luck!

http://www.babycenter.com/0_chart-how-much -sleep-does-your-child-need_7645.bc

My daughter is doing the same thing. She wakes up around 2 am every night and wants to play. She isn't hungry. I don't know about teething, but she doesn't seem to be in any pain. She sits up and claps her hands and want to crawl around exploring. It takes me 1-2 hours to get her back to sleep. So, I don't have a solution, but I feel your tiredness!