Clash of Clans
The next game on our list is an old one, but it's still one of the most popular, successful, and enjoyable iPhone games period, or iPhone games to play with a friend.
Clash of Clans is over six years old, and I've played it since the day it was released. In my "clan" I have friends in several different states, a buddy that lives in London, family members from all over town, and strangers that now know more about my life than most people. It's a great way to keep in touch with friends and have fun at the same time.
At this point, almost everyone should know about Clash of Clans. It's a top-down multiplayer strategy game where you build your own city (village) defend against attackers almost like a tower-defense game, but then can take those same troops from your village to destroy other player villages.
Over the years Supercell added clan games and clan wars, too, that way you can really compete against everyone. Download Clash of Clans, connect to Facebook, and you'll likely find SEVERAL friends and family members that play it too.