Summer is in full swing, and it's really hot outside. So why not stay indoors where it's nice and cool and play some video games?

But what do you play? There's no shortage of good stuff that's come out so far in 2015, but they can vary wildly not only in style, but in the amount of gameplay hours you can wring out of them. 

If you really want to hunker down with just one or two games that will last you until Christmas, here are some great options to keep you busy.

Cities: Skylines

This is what the latest SimCity should have been. It's a city-building simulation in which you build roads, zone for different buildings (residential, industrial, commercial), supply sufficient power and water, raise/lower taxes ... All that good stuff. Cities: Skylines is the best execution of that tried-and-true gameplay in a long time, and the developers have been continuing to make it better with additional stuff and support for user-created content.

Available on PC and Mac

Rocket League

Rocket League is like soccer with RC cars (or are they normal cars and the ball is just huge? It's not clear), and it's one of the most addictive multiplayer experiences I've had in a long time. On the surface it's incredibly simple: Two teams (of one to four players each) drive around an arena trying to knock the ball into a goal -- just like soccer. But there are no penalties, no offside rules or any of that nonsense. Just a lot of speed. 

Having two to eight cars boosting and flipping around trying to "kick" a ball gets hectic fast, but only in the best ways possible. Matches only last five minutes, which is a perfect length of time to make you say, "Sure, I have time for one more of those," after every match.

Available on PC and PS4

Monster Hunter 4 Ultimate

Monster Hunter is huge in Japan, but it doesn't have a huge audience here in North America. That's unfortunate, because its deep RPG gameplay is a lot of fun with a good group of people.

Even if you're alone, though (or playing with strangers online), Monster Hunter 4 Ultimate is a great way to kill a bunch of hours. Collecting items for better armor might be a bit of a grind sometimes, but you get a nice rush when you're able to hunt bigger and deadlier monsters thanks to your new and improved gear. And since Monster Hunter 4 Ultimate is on the 3DS, you can keep playing even if you need to be on a plane or in a car heading somewhere else for the summer.

Available on 3DS

The Witcher 3

You could compare the world of The Witcher to Game of Thrones. It's a dark fantasy world full of violence, sex and politics, where the heroes of the story tend to operate in areas of gray rather than black or white. Heads will be chopped off, clothes will be removed and the choices you make could have dire consequences. It's absolutely an epic story -- and not one that's family friendly.

It's also a game that boasts more than 100 hours of potential gameplay, and it's not joking. Sure, if you just plow through the main quest quickly you'll finish the story much faster, but if you want to hunt every monster and complete every quest you're going to be busy for a very long time.

Heck, you could spend a lot of time just playing its fantasy card game: Gwent. -- Read the full review of The Witcher 3

Available on PC, Xbox One and PS4

Planetside 2

Planetside 2 doesn't make the best first impression. It's an online, multiplayer-only shooter that basically just drops you into a huge battlefield and says, "Here you go! Have fun!" Then you're left to try to figure out the finer points of the combat while your allies suffer.

Still, when you get over the initial hump there's a lot to like in Planetside 2. It's a game all about massive battles (it holds a Guinness World Record for "biggest FPS battle" for getting 1,158 players into a single skirmish), complete with vehicles and control points and other stuff that keeps the action interesting moment-to-moment.

It's free-to-play, so you don't need to invest a cent in it if you don't want to. The downside to the free route, however, is that you might have to wait for a server to have room for you before you can jump in and start playing. Want to skip the line? You can pay for a membership, which also comes with in-game cash to spend on new weapons, etc.

Available on PC and PS4

Project Cars

If you're serious about cars and realistic racing, then Project Cars might be up your alley. It's not an arcade-like racer with boosts and crazy shortcuts -- it's an in-depth simulation that's made for the kind of people who really care about how a car looks and feels. Do you care about tuning? Then you might care about this game.

It also looks really good, graphically speaking.

Available on PC, Xbox One and PS4

Farming Simulator 2015

This is a game that tries to, more or less, simulate the life of a farmer, primarily through the use of farm vehicles.

Wait, no, don't leave. Hear me out. It turns out that without the grueling physical labor farm life isn't so bad. In fact, there's something relaxing about harvesting wheat in a zamboni-like fashion. Maybe this is a game you play while listening to a podcast or while Netflix is playing on another screen, but it's a game you could easily lose hours to.

Available on PC, Mac, Xbox 360, Xbox One, PS3, PS4, 3DS and Vita

Splatoon

I've found myself coming back to Splatoon more often than most other multiplayer-focused games I've played lately. There's a ton of cool gear to collect and fun new weapons to unlock as you complete matches, but most important, Splatoon is just a blast to play. It's fun, it's charming and it feels unlike any other game available right now. As long as there are other players online, I expect to be splattering ink everywhere for a long time to come. -- Read the full review

Available on the Wii U

Hearthstone

Maybe you're into collectible card games already, or maybe you've looked at those crazy kids playing Magic: The Gathering and have wondered what all the fuss is about. Either way, Hearthstone is a blast, and a good tutorial and solid set of single-player options make it really easy to pick up and learn.

It's also free (until you decide you want to spend way too much money on packs of cards so you can make your deck unbeatable), so you'll lose nothing but a bit of time if you ultimately decide it's not right for you.

Available on PC, Mac, phones and tablets

Marvel Heroes

If you're still in an superhero mood after seeing The Avengers: Age of Ultron and/or Ant-Man, the free-to-play Marvel Heroes is a great way to spend your time. It's a Diablo-esque multiplayer RPG that lets you play as most of your favorite Marvel super heroes, from Iron Man to Captain Marvel to Doctor Strange.

You get one basic hero for free and can purchase more as you want (or earn them -- slowly -- by playing the game). Before you know it hours will have passed, but your Spider-Man will have some sweet moves.

Available on PC and Mac

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