Seinfeld Episode 174 was entitled "The Frogger". There are 3 separate subplots in this episode.

Elaine Loves Cake

Elaine is given cake on two different birthday celebrations at work. Elaine didn't want to have anything to do with any forced socialization like that. So she proceeds to call in sick to work the next day. Upon her return to work she is given a party to celebrate her return. She then proceeds to flip out and insult her co-workers.

Later on Elaine goes into her boss Peterman's office and raids the fridge. She eats part of a large slice of cake. Afterwards she finds out that the cake she ate came from the 1937 wedding of King Edward VIII, and had been purchased at a price of $29,000.

Elaine sneaks back into the office to try and even out the slice so it looks good again, but she ends up eating the rest of the cake instead. She tries replacing it with a slice of Entemann's cake; but that ruse is quickly discovered after her boss has the cake appraised, and finds out that it is a fake. He quickly discovers who the culprit was.

Pennsylvania Dutch Country

Jerry dates an annoying woman who keeps finishing his sentences, and keeps escalating a relationship that he wants to end. This is standard Seinfeld stuff, either George or Jerry are in a situation like this in nearly every episode. Meanwhile Jerry is also nervous about a serial killer who is targeting men that look sort of similar to him.

The Frogger

George purchases a Frogger arcade game from a closing down pizza joint. He wants this specific machine because it still has his initials on the high score table. Lots of hijinks ensue as they attempt to move the machine without losing power.

Most discussions about the this episode mention the fact that Frogger never allowed the player to enter initials in the first place. But actually the Frogger related plot hole went a lot further than just the high score table, which did not seem to actually appear in the episode as far as I could tell.

First off, that wasn't even a Frogger machine. It was a Sega cabinet, and it had a Frogger marquee at the top, but it wasn't a Frogger. Frogger machines have a distinctive control panel with a treadmark design. Frogger machines may have a single large frog picture/logo on the side, but they never had black frog stickers all over the machine. One scene in the episode even had them on the back section. No old arcade games are ever decorated in back: that part faces the wall, so no one can even see it.

They powered the machine with a car battery. That is a big problem as well. The Frogger gameboard is a Konami Standard board, which requires +12 volts, +5 volts, and -5 volts power, that they apparently supplied with a standard car battery. They somehow managed to provide the needed AC power for the monitor as well. They could have possibly used some sort of power inverter to power the whole thing, except that that none of the standard ones that you buy at the store can put out enough juice to power an arcade game. Autozone sells these things—I tried—it doesn't work. A higher rated one would have drained the battery in seconds, if it even worked at all.

Then there is the little bit about expecting us to believe that the game was really plugged in and turned on for ten years without losing power once. Nope, that would probably never happen, even if the place never had a single power outage, and even if they never had to service or move the machine, it still wouldn't have happened. The monitor would have given out by then. Arcade monitors often have some pretty impressive service times, but the one on the show had a perfect picture, while a monitor that had been on for ten years non-stop would have looked horrible, and would have had a terrific amount of screen burn.