On the Penguin Live Lecture you learn a way to aparently make borrowed headphones play a song while they are not plugged in. While the effect is similar to Decibel by Adam Wilber you do not need Decibel for Jeff's version of the trick. The gimmicks are completely different.
On Jeff's At the Table Live Lecture with Murphy's he teaches a couple effects with head phones as well. One where he transfers the sound from one phone to the other, and another where he causes a headphone to levitate. For each of these he teaches you how to make the gimmicks yourself.
You do not need Decibel by Adam Wilber for the effects on either lecture.