As I was doing research for my book, I came across this incredible film put together by John Davison, who not only played the Fifth Doctor but is the father-in-law to the Tenth Doctor, David Tennant. This 30 minute video also stars Doctors Six, Seven and Eight (Colin Baker, Sylvester McCoy and Paul McGann ) and a ton of cameos by many Doctor Who alum, past and present!
Enjoy!
http://www.bbc.co.uk/programmes/p01m3kfy