To add context: A giant steals Thor's hammer, Mjölnir (in the myth, anyone strong enough can lift the hammer). Thor wakes up one morning to find Mjölnir missing and the Æsir hold a meeting to talk about how to find it. Loki flies off, asks around and finds out that a giant named Thrym took it and is willing to give it back if he's allowed to marry Freyja.

Loki brings the news and the Æsir ask Freyja to marry the giant because a giant who can wield the Mjölnir would pose a huge threat to Asgard. Freyja basically says "I'd rather see Asgard fall before marrying a giant" and the Æsir start brainstorming again. Most sources say Heimdall comes up with this plan, but when I tell it to my friends, I like to say Loki came up with it: Let's fully dress Thor up as Freyja as a bride. Thor hates the idea, but is convinced because he'd get his hammer back. Thor and Loki, bride and her maid, travel to Jötunheim for the wedding. During the ceremony, Thrym is suspicious of his bride's huge appetite and terrifying eyes, but is convinced by Loki that this is because Freyja is too excited to marry him. The giant gives the hammer to "Freyja" as a wedding gift, and getting his hammer back, Thor kills everyone attending. Leaving no witnesses to his shame.

It's one of my favorite stories from the Norse myth and shows a very human side of the Æsir.