I know a popular game with upper elementary/middle school students is Calculation Nation. Kids can create an account and play other kids from around the world! The focused areas of study are fractions, factors, multiples, symmetry, basic multiplication and calculating area.
Check out the blog post by Richard Byrne--Multiplication.com--Games and More for Practicing Multiplication--published by Free Technology for Teachers (February 12, 2013). He talks about multiplication.com where students can select from dozens of games to practice their multiplication skills. They can play single-player and multi-player games. The site offers "fact" and "quiz" navigators that students can use to refresh their memories of multiplication facts.
Illuminations also has some math interactives that are helpful in teaching multiplication concepts.