1. "The Contest"
"The Contest" was the 51st episode of the NBC sitcom, Seinfeld. The eleventh episode of the fourth season, it aired on November 18, 1992. In the episode, George Costanza tells Jerry Seinfeld, Elaine Benes and Cosmo Kramer that his mother caught him unaware while he was masturbating. The conversation results in George, Jerry, Elaine and Kramer entering into a contest to determine who can go for the longest period of time without masturbating.
2. "The Marine Biologist"
"The Marine Biologist" is the seventy-eighth episode of the American sitcom Seinfeld. It is the 14th episode of the fifth season. It was originally broadcast on NBC on February 10, 1994. Jerry Seinfeld considers the episode to be one of his favorites.
3. "The Boyfriend: Part 1" (The Magic Loogie)
"The Boyfriend" is a two part episode of the sitcom Seinfeld. It makes up the 35th and 36th episodes of the show, and 17th and 18th episodes of the show's third season. It first aired on February 19, 1992. In the 'extras' section of the Season 3 DVD, Jerry Seinfeld says it is his favorite episode. Upon its first airing it was initially titled "The New Friend".
4. "The Serenity Now"
"The Serenity Now" is the 159th episode of the NBC sitcom Seinfeld. This was the 3rd episode of the 9th and final season. It aired in the U.S. on October 9, 1997.
5. "The Summer of George"
"The Summer of George" is the 156th episode of the sitcom Seinfeld. It was also the 22nd and final episode of the 8th season. It aired on May 15, 1997.
There may be other opinions of which episodes are the best, but remember...this is my blog!