edited on 12/17
Some of my favorite discussions on Pinside are the ones about home game rooms (especially the Lets See Pics of your Game Room thread). I enjoy seeing what people have and like to get ideas for myself.
Finally this summer, it was time for me to get mine. Currently my game room is in the basement. Decent size, but has space wasters such as a full set of steps in the middle, furnace, hot water tank, oil tank, washer & drier, well water pump, etc. Low ceilings, cement floors, very few outlets, underpowered outlets, support columns, etc. Well all is about to change.
They started this week with the excavation. We are adding a mudroom to the house which will connect to the garage. House is higher than the driveway, so its 8 steps down and 5 steps up to the second floor which is the new game room. Steps are in the mudroom to maximize floor space in the room. I'll have a small 1/2 bath and a small kitchenette in the front corner. The rest is open space for games (no support columns). 28' x 36' with 8' walls and 15' cathedral ceiling..... Big Guns will fit with no issues (if I ever decide to get a Big Guns) 
Power outlets up the wazou including the walls and the floor (for islands of games), reinforced floor so the weight won't be an issue, and heating and cooling for the temp changes of New England.
I'll post progress pics as the construction moves along. Estimated completion date is early December.
Reading, MA
Kitchener, ON
