I have many favorites. Bill Kazmier rolling up a 3/4 inch thick iron frying pan like a burrito with one hand. "Sorry guys, I hurt my right arm a while back so I'll have to do this one-handed."
Gene Rychlak benching 1000lb.
But let's take a break from the lifting related feats. Four feats that blow my mind, even though they aren't PL/weights related.
1) Chris Sharma making the first ever ascent of "Realization", the world's first 5.15a rated rock climbing route (5.15 is the sport's highest grade). 130 feet of 35% overhang with nothing but small 2-3 finger pinch holds and sloping rock the whole way up. Arguably the hardest route in the world. And nowhere to really set your feet well. Every time I see the video I just want to cry. Think of it this way, from 5.10 up each decimal has four letters (a-d) that further describe difficulty.
Anything at or above 5.13 is pretty much like vertical glass.
2) Chris Sharma making first ever ascent of "Witness the Fitness", probably the hardest boulder problem (short rock route) in the USA. 40ft of dead overhang, with a perfect jug handhold at the beginning and a perfect topout, and in between nothing but tiny tiny edges and small mushroom shaped knobs.
3) Tommy Caldwell for free climbing the 25 pitch Dihedral Wall in Yosemite (5.14a). One of the hardest free walls in the world. 1 pitch=50m-60m.
4) Heinz Zak for free soloing (no ropes, no protection, no 2nd chances) "Separate Reality" in Yosemite. The crux is exposed, a roof that hangs 200m above the Merced river. There are harder technical climbs, but not many that take more balls.
I can't resist. Pics forthcoming.