I cannot stop playing Splatoon.

However, if you have a Wii U and are able to play Splatoon, odds are you already have it anyway. For something that most people can access but relatively few know about, I'd point to Town of Salem. It's free to play in a browser and runs $4.99 or less on Steam, but there's no real incentive to buy it unless you feel like supporting the devs.

It's similar to the party game Mafia/Werewolf/whatever other names it goes by, in that there is a majority of town members trying to survive by finding and lynching the minority of mafia members before they're all killed. There are a lot of individual roles that make it more complicated, but that's the basic idea. It's all about deductive reasoning and being a good liar.

And being able to tolerate the occasional abuse of Lenny faces.