I like the part in the goblet of fire when they go to pick up harry from the dursleys and get stuck behind the fire place..

Rons voice now joined the others..
'What are we doing here?Has something gone wrong?'
'Oh no Ron' came Freds voice, very sarcastically. 'No this is exactly where we wanted to end up'
'Yeah, were having the time of our lives here,' Said George whose voice sounded muffled, as though he was squashed against the wall.

classic!