First, visit Mr. House and after complimenting his snow globe collection, the player character will be able to sell their snow globes to Jane for 2,000 caps apiece. They will then be displayed in the Lucky 38 presidential suite on a stand. When the player character finds a snow globe in one of the add-ons, it will automatically be transferred to a shelf in the presidential suite and the player character will automatically receive the 2,000 caps.
When the player character first visits Mr. House in the Lucky 38 penthouse, they will be greeted by Jane, the Securitron immediately in front of one as one exits the elevator. She is also the only Securitron with a woman's face. To give her the snow globes one must exhaust the dialogue option "What's with the snow globe collection?" and then state, "I have some snow globes for Mr. House's collection." Note that if the player character kills or disables Mr. House, she disappears. There are seven snow globes in all, excluding the add-ons. Jane will give the player character 2,000 caps for each snow globe and, after selling them, each one will be added to a display stand in the presidential suite.
Vault 21, in Sarah Weintraub's room. Walk through the Vault 21 gift shop into the Vault itself. Go down the first and second staircases, turn left, move down the hall past your the player character's to Sarah's and pick the Average lock, keeping in mind that the player character will lose a minuscule amount of Karma. The snow globe is on the nightstand directly in front of one, in between the two beds.
After the player character has returned seven snow globes from the Mojave Wasteland, the snow globe stand will "sparkle" for a moment.
If Mr. House dies before all globes are collected, the ones found after his death will still automatically appear on the globe stand.
The snow globes found in add-ons are not part of this quest, but still pay the 2,000 caps (or Sierra Madre chip, in the case of Dead Money) finder's fee. Their locations can be found on the snow globe page.
The snow globes found in any add-ons will still appear on your shelf like any other snow globe.