I really liked the first season of the Magicians on Syfy, but it wasn't an immediate sale for me. It took a few episodes, four to be exact. The scene that got me hooked has Quentin (Jason Ralph) trapped in his own mind and he uses a Taylor Swift song to contact Penny (Arjun Gupta). The scene was set up an episode or two before in what looked to be a throw away scene.
While at SDCC, the cast and crew were asked about getting the rights to and performing Shake It Off. Executive Producer John McNamara explains that it cost the show $50k to secure the rights to the song and when the check was being written, he was asked to promise to never do something like that again… he refused.
Here is the section of the panel from the con and a behind the scenes look at the making of the scene.