Zack and Miri Make a Porno

Lifelong friends and roommates Zack (Seth Rogen) and Miri (Elizabeth Banks) are facing hard times and a mountain of debt. When the electricity and plumbing get cut off, they seize upon the idea of making a homegrown porno movie for some quick cash, enlisting the help of their friends. The two vow that having sex will not ruin their friendship. But as filming begins, what started out as a business proposition between friends turns into something much more. (Source)

Two lifelong platonic friends, strapped for cash and in debt, decide to make a porno. (Source)