Friendly Fire! from Red Robot Labs and Shortround Games is one of the most novel strategy games I've played in a long time. It's not particularly deep, and a lot of the enjoyment comes from the gimmick, but I'm enjoying it more than most every other freemium game out there. Basically, it's a strategy game that uses actual Google Map style street data to let you build a base on your actual street, and defend it from invaders while taking the fight to the rest of the globe.
Everything has to be built near streets. If your own street is terribly indefensible, you can always use popular locations or just a better spot in your own town. As you build your army, resource collection, and defenses, and fight other people, you'll gain medals, losing medals with each failed attack or defense, rising and falling on the leaderboards constantly. Everything can be upgraded, and everything takes time to build, like a standard freemium social game. You can speed the process up with the premium currency of gems, which are actually given to you rather generously for completing side objectives.
As you're unlocking units and defense options, the strategy of the game opens up more and more. Things are simple when it's just tanks and turrets, but soon you're dealing with scouts, mini-guns, artillery, planes, and air strikes. There is a lot of nuance that goes into sizing up a situation before spawning your units. Luckily, it's actually very easy to recover from a loss or failed attack, and repairing your base doesn't take any time at all. There is also a big emphasis on getting revenge against people who destroy your base, which leads to big rivalries.
There are better spots on my own street to build a base, but I wanted to simulate defending my actual house, and that alone has amused me constantly. It helps that the visuals and characters are colorful, vibrant, and cartoony, somewhat reminiscent of Great Big War Game. It's pretty well balanced. If your base gets destroyed, it's immune from attack for a certain amount of time, or until you attack someone else again. It's not a perfect game, and there is a lot of waiting around, but in this genre, it's one of the most fun I've ever played. You can check it out now, for free.