Seinfeld party

A party in which the participants are celebrating something which would normally not deserve celebration. These parties usually take place to end a partying dry-spell.

While Seinfeld is a show about nothing, a Seinfeld party is a party for nothing.

Guy: Hey, are you coming to the celebration, tonight?
Girl: What are you celebrating?
Guy: The date! It's 10/10/10!
Girl: ...Why would you have a whole party for that?
Guy: It's a Seinfeld party!