The very best of Birthday wishes to the following all of who guest starred on Stargate SG1 or Atlantis.
Jill Wagner
Jill played Larrin in two episodes of Atlantis as well as appearing as the lead actress in Blade The Series and a regular in the first season of Teen Wolf. She is currently hosting Total Wipeout USA. IMDB Twitter
Link Baker
Link appeared twice on Stargate SG1, first as Lt Barber in the episode The Light and then as Artok in Allegiance. He has also appeared on Smallville, Special Unit 2 and Arrow. IMDB
Michael Robinson
Michael played a councilman in the SG1 episode Revisions and also appeared on Lost, Dead Like Me, Reaper and Endgame. IMDB
William B. Davis
William made his name at least to my generation playing the cigarette smoking man in 37 episodes of The X-Files. He also played the Prior Damaris in two episodes of SG1 and guest starred on Smallville, Andromeda and Continuum. Official Site IMDB Twitter