Xenia is an experimental Xbox 360 emulator that is actively being worked on. The contributors to the project have gotten the emulator to a state where it will load and run many games, at least to the level of showing menu's and some level of gameplay.
But don't get rid of your Xbox 360 just yet; at time of writing (spring 2017) compatibility with games is still really low with only a few small games being playable. A full compatibility list is available on the project's Github page, in the form of an issue tracker.