Announced over the summer, PixelJunk Monsters Online is based on the PSN tower defense game, which has sold over 500,000 units. Now you can play it while waiting for TPS reports to collate.
PJO features the tower defense gameplay of the original along with a world map, and sees players defending their lands from waves of monsters. The objective is to collect gold and gems to expand territory and defend more tiles -- of course, your friends will be doing the same. That's when the fighting starts, followed by nasty Facebook messages, and eventually it culminates in a peace accord over buffalo wings at T.G.I. Fridays.