Usually, we logo designers will start off our logos with a font, then alter each letter to make it totally unique (so we can justify charging thousands for it). Jimmy recreated this logo to make himself some T-shirts last year because Jimmy wanted the red and yellow colors on a white shirt. Jimmy seems to remember this actually turning out to be a non-italic font which was skewed diagonally, rather than an italic version to begin with. Jimmy doesn't believe there are any commercial serif fonts with such short ascenders, or lower case "e"s which are crossed as far bove the vertical midway point as is the case in this logo. Even if you found something close, it would drastically change if you simply clicked on an italic style button in a word processor.
Anyway, yada, yada, yada... Jimmy thinks he may have ended up just redrawing it from scratch in Adobe Illustrator. If anyone's interested, Jimmy can email the logo (an ".eps" vector file, which can be enlarged limitlessly without loss of quality) to them, or even better, upload it somewhere, if Stan can instruct Jimmy with that. Otherwise, if it's the "font" you prefer, for writing other words beside Seinfeld, check some "tv show font" websites. Hacks are always recreating Star Trek, Flintstones, and every other famous typestyle under the sun... but don't be fooled... most will only have the actual "logo characters" looking good, while the rest of the "guesswork" alphabet often appears very non-uniformed with the rest, and quite amatuerish. This site below has some so-so quality one's Jimmy's used in the past (but no Seinfeld yet). Bookmark it and check it ocassionally... or maybe write to them and request it.