Both games I am in, one I GM AD&D and the other I play in is Weird Adventures. Both have hit shifts in the game. With the Weird Adventures games our group has solved the first mystery and will be moving on to the next. We've established our characters and we've learned about the system and setting so I think our next mystery will have us working together in a whole other level.
The AD&D game has taken a strange turn. The players have fallen into a 'pit'. Where they all find themselves in a different realm. This game has been one where the realm they are in shifts the focus of the game. Where most of the time its the level of the characters that shift it from dungeon delving to establishing an stronghold or kingdom.
This is act 3 for my players. While I had the beginning realm fairly well mapped out and set up and the second part fairly setup, this third part was totally unexpected and it's got my juices flowing of what I present to them. A change of scenery can be a good thing. Especially for a GM.