I listened to a whole bunch of these videos, and while I wasn't measuring my memory, I did pay close attention to how the sounds made me feel, and this one particular made me feel strangest: [1]. Unfortunately, the sound fades in and out and the effect goes with it. I wish it could have had stayed at a steady volume so that the effect could be sustained. If you watch it, just ignore the cheesy graphics and listen.
Here are some other interesting ones: [2], [3], [4], [5], [6]
Video [3] is actually supposedly 40 Hz.
[1] - https://www.youtube.com/watch?v=2-eTVW8VMRQ
[2] - https://www.youtube.com/watch?v=xG22hV-gMsY
[3] - https://www.youtube.com/watch?v=ZGHbKWGgH_E
[4] - https://www.youtube.com/watch?v=lhZPMTpW-gg