Up until now we've needed Windows 10 if we wanted to play wirelessly using an Xbox Controller on PC. However, finally, the Xbox Wireless Adapter supports Windows 7 and 8.1 as well. This was announced by Major Nelson over on Twitter.
So now you can play your favourite games on PC without any cables (unless, you know, you're still using Windows XP), and the functionality comes with a relatively easy setup. The adapter supports up to eight wireless controllers, plus up to four chat headsets or two stereo headsets.