best one in my opinion was the episode where Lisa starts to like Nelson...
If you can't remember it this is how it went;
Lisa writes a love note to Nelson who sits 2 seats away from her;
She passes the note to Milhouse who has no clue what the note ie about, he passes it to Nelson;
Nelson receives the note from Milhouse, opens it, and it says something like "i like you";
Nelson looks at Milhouse with this disgusted look on his face, and Milhouse not aware of what was written in the note, just smiles back at him and gives him a waive;
LOL
Next thing you see - Milhouse is being taken away on a stretcher all f'd up...