For more on synesthesia, follow these links:
The Synesthesia Battery
Want to know if you are a synesthete? Take the tests on The Synesthesia Battery to find out.
Synesthesia on NOVA Science now
A profile of the synesthesia research in the Eagleman lab.
Synesthesia on Discovery Channel
For a quick overview of synesthesia, see this 6 minute video with Dr. Eagleman on the Discovery Channel.
Synesthesia on Research Channel
For a slightly longer overview, see this 8 minute video with Dr. Eagleman on the Research Channel.
Lecture on Synesthesia
For a more complete view of the phenomenon, see David Eagleman's 1 hour talk at the University of Sydney.