From the many moments in the Astérix books, this troper always laughs at a certain moment of Asterix in Corsica, where a boat is sunk by an explodingcheese. Seriously.
Asterix trying to sell a herd of boars, and ending up in a shouting contest with another boar salesman. Made doubly funny by Obelix refusing to rise to the occasion.
Boar Salesman:BOARS, BOARS! BEST PRIME BOARS!
Asterix:BOOOOOOOAAAAARS, BOOOOOOAAAAARS, BEST PRIME BOOOOOOOOOOAAAAAAAARS!!!
Obelix: (Very quietly) Boars, boars, best prime boars.
The Roman orgy illustrated in Asterix In Switzerland. Also, from Asterix And The Secret Weapon, when the female legionnaries have gotten instated. (Their introduction also qualifies, with all of the legionnaries having a reaction in the vein of Head-Tiltingly Kinky.)
Legionnaire 1: If women can join the legions now, what use are we going to be?
Legionnaire 2: I could tell you! I wouldn't even mind being a domesticus in that camp!
In Asterix and Cleopatra, the captain of the boat ferrying the stone for the palace has been bribed to "lose" it. He orders his workmen to throw the bricks into the Nile. One guy comments an owl, a person (both underlined), a symbol (which one this troper cannot recall), and a feather (caption "'Bain't no use arguing with he". Another guy comments an owl laughing madly, a person tapping his head (both underlined by a wavy line), a symbol that has fallen apart, and a tattered feather (caption "Oi reckon gaffer be crazy").