During Shloshim and the Year, while mourning for my mother, may I watch television or movies at home, and/or play games on my tablet either alone or with friends?
Without getting into the issue if one should watch television or movies, because of the negative content and images that they contain, it is permitted for an avel to hear backround music that accompanies something that is being done, such as the backround music of a program, or when one walks into a store, or from the ringing of one’s cellphone. The reason for this is since such music doesn’t bring a person to excessive, and it is there for a different purpose, it is permitted.
Regarding playing together with friends, that is tricky and it depends on the circumstances, because it might be considered a social gathering, which will cause the avel to have excessive happiness, which is not appropriate for this period.
Nishmas Yisroel 2- 537, The Laws of Aveilus pg. 223.