Some people never retire, most people retire and stay home or travel as tourists, and some people take advantage of their retirement years to work abroad. Now unless you are a medical professional or highly-paid management consultant you probably won't earn much in this type of work, but it is a great opportunity to try something new, to stretch yourself in a different culture.
There are government or quasi government programs available in some countries, such as the Peace Corps http://www.peacecorps.gov
in the United States, which accepts volunteers of all ages for stints of a year or more. In Canada, a group called CESO http://www.ceso-saco.com
uses volunteer help for various assignments that usually last two to four weeks but can be up to six months. The emphasis in the latter group is on business skills, while the Peace Corps has a lot of openings for English teachers, community workers and others.
If you are really adventurous and hard-working, you may be able to piece together volunteer gigs overseas on your own. I know a woman who is a semi-retired psychologist and spends about half the year offering psycho-spiritual workshops to underserved populations in some of the world's most remote and impoverished regions. She works in places such as Paraguay, the Dominican Republic, South Africa and the Philippines.
It helps that she is able to offer her services in English, French, Spanish, and Afrikaans, and that she works mainly with religious or other non-governmental organisations abroad and in Canada.It's even more impressive that she manages it without the assistance of a big pension..
So, if work at home has dried up or become stale, consider taking your show on the road. As they say, a rolling stone gathers no moss.