Jerry, Elaine, and George go to a Chinese restaurant for dinner before going to a movie - a rare theatre showing of "Plan Nine From Outer Space". Jerry is correct when he says it's the worst movie ever made, but I digress. The proprietor tells them it will be 5 or ten minutes, but the waiting drags on in real time as they watch group after group get seated before them and even one guy who just walks in off the street, but is clearly chummy with the owner. Meanwhile, George needs to call a new romantic interest, Tatiana, but the guy on the pay phone is talking forever and just smiles when George says he badly needs to use the phone. This is the set-up for the comedy consisting of the growing frustration of the group and in Elaine's case, severe hunger.
It is the first episode that really pushed the envelope for Seinfeld. Certain executives at NBC thought it would flop because it was shot entirely in one location, but they let Larry David do it anyway. It was well received, mostly because it was actually pretty relatable at the time. It's so aggressively about nothing, yet it has all these bits of urban life that resonate (or did at the time). The dilemma of when to cut bait on a reservation, the sense that the reservation guy has made a mistake, the frustration when you need to make a movie time, the protocol over time on a pay phone. It's all that minutia that is actually compelling in the moment, even though it's absolutely trivial.
One interesting point - It is one of only two episodes with no Kramer at all.