How do teams work together? What motivates them and leads them to success? Indeed, can project managers inspire teams?

Teams are formed when individuals are thrown together and given a set of challenges to overcome. Sometimes the individuals are selected on the basis of capabilities, or competences, but often they are not. The team is then expected to coalesce and ultimately perform at some higher level that feeds on the synergies that emerge when the parts come together to make the team. So how do teams become inspired?