We hear that question from people who show an interest and are potential members.  What's your answer? One good one is:
Rotary club members are part of a diverse group of professional leaders working to address various community and international service needs. Through community service and other means, Rotary club members help promote peace and understanding throughout the world. Our members are our most important asset. They are the force that allows Rotary to carry out its many humanitarian efforts and achieve its mission.

Another answer would be to describe any one of our great SERVICE projects that will relate to the interests of the person if you happen to know them.  Youth Exchange, Group Study Exchange support, hands on help for the other partners in the community, Polio Plus, Club and personal Foundation contributions, social activities, opportunities to serve in local and international service activities, and the excellent friendships with all Rotarians both here and the world over. 

You can also say that the person wearing the Rotary symbol (example, your pin) is saying that he/ she is a person that can be counted on, has high personal and professional ethical standards, and is a friend.  In fact, if you wear your pin, people will ask you what it is for if they don't already know! And they will probably want to join us!!
by Glen Agar Rotary Club of Kapuskasing