Marshall fears being yelled at by his boss, who is nicknamed "Artillery Arthur," after failing to complete a report (about decertifying a class action due to lack of commonality and numerousity) on time (which is nicknamed the "Ninja Report" for easier understanding for the gang). Robin, Lily and Ted each describe how they would deal with Arthur's aggression, and Barney explains that Marshall shouldn't deal with it - the way that the chain (or circle) of screaming works is that one person screams at someone "below" him, then that person screams at another person, and so on. Barney and Marshall go to a diner and Barney urges Marshall to scream at the waiter, but Marshall cannot do it - the waiter screams at Marshall instead. The next day, Marshall finally lets out his feelings towards Arthur and, in the end, quits his job at Nicholson, Hewitt & West.

Meanwhile, Ted has bought himself a new car, a blue Toyota Camry Hybrid. All of his friends think a nice car is totally unnecessary in New York City and proceed to eat ice cream and smoke cigars inside the car, despite Ted's protests. Eventually, Ted sells the car and gives the proceeds to Marshall to help pay for the apartment since he no longer has his high-paying job.

 

http://en.wikipedia.org/wiki/The_Chain_of_Screaming
http://how-i-met-your-mother.wikia.com/wiki/The_Chain_of_Screaming