The Telegraph is reporting results of an Oxford University study which found that playing Tetris shortly after a traumatic event may help to reduce symptoms of Post Traumatic Stress Disorder (PTSD).
The article cites one involved researcher referring to a six hour window during which it is "possible to affect certain types of memories that are laid down in the human mind," and speculating that the breadth of the brain which is involved in playing Tetris may interrupt that processing of memories. If that is the case, it may be that PTSD symptoms could also be reduced by other activities which stimulate large portions of the brain, though what those would be I know.