Quick video of some of the better Tandy Color Computer games:
http://www.youtube.com/watch?v=H2QlXXU0waw
And a link to some games that have been released to the public domain by their copyright holders:
http://www.voltage-control.com/cocotrns.html
The result of released code -- The Daggorath PC project:
http://mspencer.net/daggorath/dodpcp.html