Karaoke nights are the best! But they can be just another fun thing to do at your party. They are really easy to organize and thanks to YouTube lyrics videos anyone can do it with little to no equipment.
Make a playlist with lyrics videos and also write it down on a list. Your guests can then choose from the list which song to sing. Roll the music and the lyrics video and let your guest sing.
Eventually people will start to sing along and everyone will have fun!