Interesting points everyone! :) Also, I'm sorry for forgetting about Floyd/Janice and Gonzo/Camilla! :(
But as for friends, Statler/Waldorf, Fozzie/Kermit, Kermit/Gonzo, Gonzo/Rizzo, Rizzo/Pepe and Gonzo/Rizzo/Pepe are good "couples", one being a threesome. :p