Penny, Sheldon and others in “The 21-Second Excitation”

[While watching Raiders of the Lost Ark] You know, I could totally rock a hat like that.

That's the work of noted Hollywood costume designer Deborah Nadoolman. She also designed the iconic red and black jacket in Michael Jackson's Thriller video, which I've never watched in its entirety as I find zombies dancing in choreographed synchronicity implausible. Also it's really scary.

Can somebody please turn off the Sheldon commentary track?

There's no switch, just listen and learn.