Here are quite a few I thought of:
The 'E' Sketch:
Harvey Kneeslapper: Um, 'scuze me, did I ever send you e-mail?
Black-Haired Fat Blue Anything Muppet: What's that?
Harvey Kneeslapper: I say did I ever send you e-mail? A'ha ha ha ha ha!
Black-Haired Fat Blue Anything Muppet: No.
Harvey Kneeslapper: (slaps the huge purple letter E with a stamp on the AM's chest) Here's your E-mail!!! A'ha ha ha ha ha ha ha ha ha ha ha ha!!!
(The AM runs off, ending music plays)
The 'F' Sketch:
Harvey Kneeslapper: Um, 'scuze me, did you ever get an 'F' at school?
Black-Haired Fat Blue Anything Muppet: What's that?
Harvey Kneeslapper: I say did you ever get an 'F' at school? A'ha ha ha!
Black-Haired Fat Blue Anything Muppet: No, I never got it on my tests at school.
Harvey Kneeslapper: I think you DO get a 'F' today at school! (Slaps the letter F on the AM's chest) A'HA HA HA HA HA HA HA HA HA HA HA HA!!!
(The AM runs off, ending music plays)
The 'K' Sketch:
Harvey Kneeslapper: A'ha ha ha ha ha ha! Are you Okay?
Black-Haired Fat Blue Anything Muppet: What's that?
Harvey Kneeslapper: I say are you okay?!? A'HA HA HA HA HA HA!
Black-Haired Fat Blue Anything Muppet: Yeah, I guess I am.
Harvey Kneeslapper: (Slaps the letter K on the AM's chest) All right, you're O-K to go! A'HA HA HA HA HA HA HA HA HA HA HA HA HA HA!!!
(The AM runs off, ending music plays)
The 'O' Sketch:
Harvey Kneeslapper: A'ha ha ha ha ha ha!!! Would you like me to owe your money?
Black-Haired Fat Blue Anything Muppet: 'Scuze me?
Harvey Kneeslapper: I say would you like me to owe your money? A'ha ha ha ha ha ha!
Black-Haired Fat Blue Anything Muppet: Yeah, sure, I'd love to owe my money. (Gives money to Harvey)
Harvey Kneeslapper: (Slaps the letter O on the AM's chest) A'ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha!!!
Black-Haired Fat Blue Anything Muppet: (who is getting really, REALLY angry now) Aaaaaagggghhh! (runs off angrily to chase Harvey, ending music plays)
The 'W' Sketch:
NOTE: Bert and Harvey are about to appear in the same sketch
Harvey Kneeslapper: A'ha ha ha ha ha ha! Do you know what U + U equal to?
Bert: What's that? I can't hear you.
Harvey Kneeslapper: I say do you know what U + U equal to? A'ha ha ha!
Bert: Yeah, the letter W. And you know, W is my favorite letter.
Harvey Kneeslapper: (Slaps the letter W on Bert's chest) Okay, here's W! A'ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha!!!
(Bert likes the letter W, but he does not like the jokes from Harvey.)
Bert: You know, I like the letter W, but I never like silly jokes from Ernie. (Gets really mad now.) Mmmmmm! ERNIE!!! (Runs off, ending music plays, but I doubt that it's not Ernie, it's Harvey!)
The 'Y' Sketch:
Harvey Kneeslapper: Um, 'scuze me, do you know why I'm here?
Black-Haired Fat Blue Anything Muppet: What's that?
Harvey Kneeslapper: I say do you know why I'm here? A'ha ha ha!
Black-Haired Fat Blue Anything Muppet: No, why?
Harvey Kneeslapper: Because I like to know why! (Slaps the letter Y on the AM's head) Ooops! Am I bad! (Takes the Y off the AM's head and slaps it on the AM's chest) A'ha ha ha ha ha ha ha ha ha ha ha ha ha ha!
(The AM runs off, ending music plays)
The 'ICUP' Sketch:
Harvey Kneeslapper: Pssst! Hee hee hee hee hee hee. I see you pee!
Black-Haired Fat Blue Anything Muppet (who is now played by Jerry Nelson): What?
Harvey Kneeslapper: (Yelling) I see you pee!
Black-Haired Fat Blue Anything Muppet: Where? Where?
Harvey Kneeslapper: Right here!! (Slaps the letter I on the AM's chest) Here's I! Next, I will give you a C. (Slaps the letter C on the AM's chest next to the I) And up next is U! (Slaps the letter U on the AM's chest next to the C) Now, here's P. (Slaps the letter P on the AM's chest next to the U) I see you pee! A'HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA!!!!!!!!!!!
Black-Haired Fat Blue Anything Muppet: AAAAAAGGGGGHHHHHHH!!!!!!!!!!!
(Ending music plays, AM begins to chase Harvey angrily)