Thirty years ago, MTV actually played music videos. And the network played a lot of Madonna videos. So many, in fact, that it devoted an entire day — Oct. 30, 1986, also known as “Blue Thursday” — to Madge’s “Make My Video” contest, running a marathon of fan-made “True Blue” music videos that ranged from semi-professional film-school projects to amusingly amateurish camcorder clips of tots in ballet-recital tutus or tweens in Desperately Seeking Susan lace hair-bows lip-synching into hairbrushes. ...