This article, from the "Infendo" (Nintendo-oriented) website claims that senior citizens are more active in the videogame scene than is popularly believed. Here's the link to the "Infendo" article:
http://www.infendo.com/video-games/todays-senior-citizens-are-the-true-h...
Here's a related link, from the "Pew Research Center" website, claiming that more than half of all adults play videogames in one form or other. This is the study that is referenced in the above "Infendo" article:
http://www.pewinternet.org/PPF/r/269/source/rss/report_display.asp