TL;DR: I found an Easter Egg on Electronica 2 (some weeks ago - on the EI premiere day to be exact). Full story below.
Some of you might be aware that there are secret messages hidden on Electronica 1/2. When I solved the hardest one from E1 (the binary-encoded coordinates of Place de la Concorde; see here ) I got a gift from JMJ and then a couple of months later had a brief private meeting with JMJ and Stephan Gervais. They told me that the riddles in E2 are harder because (and I quote JMJ directly) "you said they were too easy for you!" (as it turns out the expectation was it would take months while it took some 9 days... so there you have it - I somewhat influenced the audio content of E2! . I told them that I found the image of a "Bode Frequency Shifter" in the spectrogram of "Switch on Leon" (between 4:24 and 4:26) and thus I suppose that the audio needs to be somehow processed to reveal the mystery and they smiled and nodded. I suspected that if anything is hidden there it's likely in the inaudible zone, around (or likely above) 20kHz. So I removed everything below 20kHz and applied a frequency shifter to lower the frequency by 10kHz-20kHz. That, however produced no results and I kind of gave up.
It was until a few weeks ago that I noticed something odd in the spectrogram of one of Stephan's "Triptych" pieces - some odd lone shapes around 20kHz. So I applied the same technique and... turns out there was something there! So I loaded up "Switch on Leon" again and looked at the spectrogram again - as this time I knew what to look for. And there it was. I wouldn't have noticed it, because it was not really separated from the actual audio content. It's hiding just below the edge of 20kHz, so my pre-filter was killing it (otherwise I would've found it two years ago!) So this time I did the -20kHz frequency shift without any pre-filtering and... voila. "Switch on Leon" hides an entire minute of an interview with Salvador Dali (from 1:12 to 2:15). You can try it out yourself if you have the lossless version of the album (CD/WAV/FLAC - mp3 won't do) and proper tools.