How to entertain yourself for 12 hours at Changi International

I arrived in Singapore a little after 2am local time and have been roaming around terminal 3 ever since. The airport is huge, complete with all of the usual amenities... swimming pool, hotel, movie theater, koi pond, and of course a butterfly garden with a waterfall.
Although I have such a long layover I only have a few hours of actual daytime during which I could leave and according to the woman at information there isn't much to see in the area aside from a shopping mall, so I'm just killing time here instead. Fortunately there is free wifi throughout the terminal and I found a massage chair that gives full body massages. I think I might even head up to the snooze lounge and take a nap before lunch.