It's based on The Vending Machine! These pretend bags come in five lovely colors!

Red
Blue
Yellow
Green
Purple

Every two days we'll add a new color!

Here's how it goes

Post
User A opens a (insert color here) bag


Reply
in it was (insert random object here)

User B opens a (insert color here) bag

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Example:

User A (posting user):
AlexK2011 opens a blue bag

User B (responding user):
in it was a cheeseburger

User B opens a purple bag
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sounds easy enough, right?