DT - Transition Games Manual - 2016
Transition Games put the game situations worked on in the C drills into games using one puck and no whistles. The players change on their own and the coach is freed to teach when the players return to the line-up. Game reading skills, hockey IQ, are developed because actual game patterns develop and the player must read the game and finish each play.
Keep score and create any situation you want to work on.
I don't see Transition Games used very much by most coaches at the minor hockey level but I do see them used at the highter levels by coaches like Mike Babcock and Finnish and Russian Olympic coaches like Erkka Westerlund and Vladimir Jursinov.