I have seen the "wife agro" coment so many times I feel the need to try and answer, sadly nothing I have ever sugested in the past ever worked; claiming youre debuging the software on the pc works untill she checks in on you, saying your downloading nasty porn either gets her interested, discusded, or baned from the cp, among other things. Saying your organising personal videos and pictures gets you booted from the pc, baby photoes gets you booted quicker; anything having to do with a remote seems to work, useing remote and computer in the same sentance is another issue. Telling her "I'm gameing and thats all there is to it", is like saying, " I love the couch and your scary personna, no realy the scary personna turns me on, Honny?".
You can use the plutonium trick...uh, lets not go there, we'll avoud the sisters thing, the puding and the bull, dont ask about the bull.
Best on a serious note is depresion, otherwise tell her you had looked forward to playing a certain game, honesty and all, youll still get the couch, just dont do that more than you are agreable with her.