Another lecture which was memorable dealt with the sheer variety of different situations and biomechanisms which you can rule out using the Second Law of Thermodynamics. The bottom line is that when you're at thermal equilibrium then everything must jitter thermally by the same amount, which is what excludes "Brownian ratchets"  from working: if you peek inside at the spring and asymmetrical "teeth" inside an actual ratchet, then you realize that the work extracted actually comes from heat-transfer to the spring, which is being implicitly assumed to be at 0 temperature in the naive "oh, you get energy out of nothing!" argument. It's a very simple 2nd-law argument to make, but really hard to poke around inside and figure out what's going on internally.
Or screw through it ;)
I recall with glee the shock of recognition that all creatures live in moving fluids -- and our experiences are delineated merely by relative sizes and viscosities.
Maybe it's nerdy to say so, but it was definitely one of the top ten epiphanies of my life, and definitely helped me feel more connected to the natural world.
I think I made it more understandable but who knows. Was def fun to read and interpret. Highly recommend.
In particular, there is a nice illustration of "inertia doesn't matter" at 15 minutes.