I'm making a example capx right now but in the meantime:
Here's a little plugin I made:
dropbox.com/s/nuf5zq2dv3jwtgt/spilgames.zip
The only thing it does is adding the spilgames API to the index.html so you don't have to add it manually each time you export your project. It's a huge time saver.
I talked with spilgames and they said that the ads are not showing right now because their API isn't complete right now and are testing things. So there is no way for us to test it right now. I suppose they use a local environment on their side to test the ads.
Actually my implementation is pretty similar to the one bilgekaan did. but you are now seeing the ads because of what I said.