Were there any inside jokes or refrences in the show? Just curious.

Superman seemed to be an inside reference. Also the Sid Fields name is maybe a reference to Jerry's comic heroes. There were also many names used on the show that were actual people connected to the show creators, such as Alec Berg, Papanick the horse, and Lloyd Braun.

Chalk full of 'em... too many to list... one of my favorite elements of the show :)
There were plenty of jokes on itself re: shows about nothing, cushy time slots (Jer talking about Bania, but refering to shows thaat followed his), etc... I'll post them as I see them.

re Sid: copied & pasted this from another of our threads;
>>>and..
as we know... Jer liked/referenced Bud & Lou... the real Sid Fields was an actor/writer who appeared/wrote on a few Abbott And Costello projects (TV & film)
http://us.imdb.com/title/tt0044229/
http://us.imdb.com/name/nm0276352/
In similar fashion, real actor Sid Fields frequently played himself, or character "Sidney Fields"<<<

I think all that stuff is fascinating. List a few if you've got a chance.

Larry David making all his cameos (& using just his voice) is kind of "inside" humor, if you didn't know who he was, you would never even notice his appearances.

Not so much humor... but on the "inside" vein, this tid bit is from some old maestro post/notes:

>>>Kal Varnsen.
Most of us know this to be Jerry's alto ego/alias/nic-name.
It's generally thought to be used in honor of Jerry's [real] dad, Kal Seinfeld...makes sense.

If you watch closely on some episodes (not sure which), when the gang is outside, in the back drop you may see signs advertising, "Signs by Kal" or "Kal's Signs." [Real] Kal Seinfeld was a sign maker.

Another [& I believe] lesser known Kal reference would be another Superman tie-in. We all know his earth name was Clark Kent but the Man of Steel's real, or Kryptonian name, is Kal-El. Tuff to plan that one [;)]<<<

All of their alias/nic names that they re-used lean toward the repeat audience.

*
166 The Strike

Denim Vest got a fake # to give to Tyhpoid Elaine off the side of a truck that clearly read:
"Azzarri Moving And Storage."

Tho Azzari was the set's production designer, the one who has control over such things.

When Kramer is chased by the Cable Guy, it can be noticed that there is an obvious product placement of Rold Gold Pretzels that Kramer is eating out of his grocery bag. A product that was being endorsed by Jason Alexander.

Here's a good one Elaine. A great insider joke.

This is from The News Guy(Mike) (with The Lists (http://membres.lycos.fr/tnguym/) site), so it's a good source.

>>>Jerry said on the Tonihght show, May, 1998 that he would NOT give the set to the Smithsonian. He said he did not want it to end up like the arc in Raiders of the Lost Arc.
And that is the background and "in joke" in the episode The Merv Griffin Show.<<<

The joke:
K: "Aahh, this looks familiar…"

J: "Of course. It's garbage."

K: "No, no, no, no. These brown things. The chairs. Jerry, this is the set from the old Merv Griffin Show!" (he climbs into the dumpster) "They must be throwing it out. This stuff belongs in the Smithsonian!"

J: "Yeah, at least in the dumpster behind the Smithsonian."

It seems the infamous "Hipster Dufus" we all associate with the Kman began as an inside joke. Appartently, the use of the term on the show was Jerry's rebutal to an article.
The term was aparently NOT coined by Jer, but by Francis Davis in an issue
of The Atlantic / The Atlantic Online December 1992 (http://www.theatlantic.com/issues/92dec/seinfeld.htm)

quote from article:
>>>"for Seinfeld and his surrogate family of thirtysomethings, which consists of his ex-girlfriend, Elaine Benes (Julia Louis-Dreyfus), his best friend, George Costanza (Jason Alexander), and Jerry's across-the-hall neighbor,
a hipster doofus known simply as Kramer<<<

Hipster Dufus was uttered on the show in
062 Handicap Spot (aired 13 May, 1993) (by Kman about himself)
067 The Glasses (by Elaine about K)