There is a QR code on the side of the counter of the comic book shop. If you scan it, it will take you to the page of The Comic Center Of Pasadena.
The sword that is featured in the opening shot was an actual sword from Game of Thrones (2011). It was valued at $10,000 and Johnny Galecki was reluctant to wield it.
The Longclaw sword from Game of Thrones (2011) can be seen in the rest of the series, first hanging on the apartment wall, and later next to the front door with a commemorative plaque that reads 'Winter Is Coming'.
Amy calls Sheldon "a left-handed monkey wrench". Many tools are specific for left or right hand, from single bevel broad axes to scissors. If some class of objects is usually right-handed then a left-handed version would be oddball. But "left-handed monkey wrench" is a tool user's joke; monkey wrenches are symmetrical, every one is both left- and right-handed. Sending a newcomer out to get a left-handed monkey wrench was a way of making fun of the noob for not knowing about wrenches being symmetrical.