Ah, there are so many really!!
Season 1: The stock tip, Episode 5. Where George receives a stock tip, and he and Jerry take the financial plunge.
Season 2: The Pony Remark, Episode 2. Where Jerry insults Nana in regards to the pony.
Season 3: The Parking Garage, Episode 6. Where the gang goes shopping for Kramer's air conditioner.
Season 3: The Limo, Episode 18. Where George convinces Jerry to take someone's limo from the airport.
Season 4: The Bubble Boy, Episode 7. Where Jerry agrees to a side trip to see Bubble Boy.
Season 4: The Contest, Episode 11. Where the gang has a contest to see who can go the longest without pleasuring themselves.
Season 5: The Lip Reader, Episode 6. Where Jerry dates the deaf woman.
Season 6: The Understudy, Episode 24. Where Kramer is obsessed with Bette Midler.
Season 7: The Soup Nazi, Episode 6. If you're any type of Seinfeld fan, you know what I'm talking about.
Season 8: The Bizarro Jerry, Episode 3. Where Elaine starts hanging out with look alikes of Jerry, George, and Kramer.
Season 9: The Serenity Now, Episode 3. Where George works for his dad.
I love them all, but those are my favorites.