Stardew Valley is the perfect game for getting your friends or significant others interested in gaming as a whole. It's simple to pick up, the art style is charming, there's plenty of things to do in each in-game day, and the atmosphere is so relaxing it's easy to lose actual days tending to your farm. But if that just wasn't enough, you might be interested to hear that the latest beta update has now also added multiplayer support!
You can play with up to three other people, though if you're starting from an already existing save you will need to build them a cabin to live in. Don't worry though, the cabins are fairly cheap and can be built incredibly early if you prioritize them. On the other hand, if you don't mind starting fresh, you can also create a new farm with co-op enabled from the very beginning.
If you would like to give the multiplayer a try, as well as offer the developers some much needed feedback, you should head on over to Steam. Simply right click on Stardew Valley, go into Properties, then into the Betas tab, and from there you will need to input "jumpingjunimos" into the text box. Once you're done just click the "Check Code" button and you'll be ready to start after a quick download.
Before you dive in, however, make sure to back up your save files! Your old saves will work perfectly fine in the newly introduced v1.3, and they can even be used to host multiplayer games, but if you ever decide to bring them back into v1.2 I'm afraid they will simply break. So just err on the side of caution and make a backup, it only takes a couple of seconds.
Have fun, and make sure to deliver any feedback you might have over at the official forums.