About workplace teams- groups brought together in an effort to make change, seek input, tackle problems and issues:

Why Be Part Of A Team?
You’ve been asked to participate on a team to accomplish some task. Immediately your decision-making process begins.

* What is the purpose of the team?
* Is it a topic that interests me?
* Who will be on the team with me?
* What kind of authority will we have?
* Is it important to management?
* What is the reward for participating?
* What is the risk (perceived as punishment) for not participating?
* How long will it run?
* Will I be better off as a result of my participation?

And:

Factors That Influence Team Motivation

I. Purpose
I have asked people for years to describe the characteristics of their most successful and rewarding team experiences. At the top of almost everyone’s list is a clear purpose, focus, or mission. But further, for long-term motivation, it must be a purpose or mission that they find aligns with their personal wants and needs.
[…]
II. Challenge
Another term that I hear frequently when I ask about team motivation is challenge. The human species, as with most animals, has been given a survival mechanism called fight or flight syndrome. When presented with a challenge, our defenses are alerted to move us to action….to run away from danger or address it directly.
[…]
III. Camaraderie
If one studies highly effective groups, one finds that the most successful groups over the long haul tend to address both the technical needs and human needs. These groups are at the same time competent in the work they perform and highly functional in their interpersonal relationships. The group is well balanced in both technical and human skills.
[…]
IV. Responsibility
In general, people and teams are stimulated by being given responsibility. Having ownership of an identifiable block of work is a long-held tenet of motivation in groups.
[…]
V. Growth
Finally, personal and team growth can provide another basis for sustained motivation. When people feel they are moving forward, learning new concepts, adding to their skill base, and stretching their minds, motivation tends to remain high. Personal growth adds value to the individual, enhancing self-esteem and self-worth.
[…]
VI. Leadership
A good leader can be a catalyst for motivation in the short term, but the best leaders create the conditions for the team to motivate itself.

Lots of other good stuff here.