You’re walking down the street. A person a few feet ahead of you drops their wallet. You pick up the wallet and run after them as they turn into a dark alley, but they're gone. When you open the wallet you knew you were meant to find it.

Write a story starting after finding this wallet

Take a random book and begin your story with the last line of that story

You could pick the first book you see from your bookshelf. You could throw a dart at a stack of books and use whichever one is lands on. What about asking a stranger to let you write down the last line of the book they reading?

"We shouldn't be doing this, you're my conjoined twin.".

Here is a piece of dialogue. Write a story incorporating it