In this paper we describe a user-centered approach to designing and evaluating a socially interactive mobile game for the elderly. The objective of the game is to encourage the elderly to socially engage amongst themselves and to make the time that they spend in the community center more enjoyable. The design of the game, known as Walk 2 Win was done for and with the elderly. Two levels of the game (easy, difficult) across two modes (single, multi player) were evaluated with the elderly in a community center over two sessions. Our results show that senior citizens are keen to play simple games having uncomplicated rules as long as they can customize the game according to their whims. Their preference lies in playing games that are enhancements of existing games that they usually play. It was found that the elderly expressed a strong preference and interest to build a team, with for example their grand children. Additionally it was revealed that games for the elderly should incorporate everyone, regardless of gender or their role in the game. The methodological lessons that we came across throughout the design process are also presented