What class-based multiplayer shooter was developed and published by Valve in 2007?

Team Fortress 2

Who was Zeus's father who swallowed his children to avoid overthrow? What classic strategy videogame has civilizations developing from the Stone Age to the Space Age? Which food item is traditionally hidden inside a King's Cake during celebrations in parts of Europe? What genre of music did Louis Armstrong primarily perform? Who was the frontwoman of the band The Cranberries?