Wasn’t there an apparition of Mary that happened on live television?

Reported Marian apparitions do sometimes make the news, but I don’t know of any actual apparitions caught on camera. There are no “recorded” images of Mary captured on live TV or film.

That said, there are several videos showing the visionaries of Medjugorje allegedly experiencing apparitions of the Virgin Mary. You don’t see Mary herself in them, but you do see the visionaries smiling, praying, and reacting (you can see these on YouTube). As regards the authenticity of these apparitions, the Church has not made a definitive statement on Medjugorje, and will not do so until the apparitions stop. More information on Medjugorje can be found here.