The father of Gordon's love interest the HalfLife 2 series is in one of the picture phone adds (he is the grandfather seeing his grandchild for the first time). I was in the kitchen when I heard that voice - I have played so much HL2 that I could not miss it. Then I saw him and the rendering was perfect - down to the beard.
I love that game and drift back to it occasionally - I just wish they would release another episode.