If you haven't been to this website, you should definitely check it
out:
http://www.gamesforchange.org/newindex
These are serious games in all sorts of formats. Some are free, and
some are for sale (but usually have free demos). Many of these would
be excellent to start discussions and help students explore a diverse
range of topics listed under headings like Global Conflict, Economics,
Poverty, Human Rights, Public Health and others.
Enjoy!
maggie