One of my favorite laughs is Tom Hanks as Woody in the first Toy Story:
BUZZ: You're mocking me, aren't you?
WOODY: Oh, no, no, no -- BUZZ LOOK, THERE'S AN ALIEN!!!
BUZZ: Where...?!
WOODY: BWA-HA-HAAAAAAAHHHHHHHH...OH-HO, OH-HO-HAAAAAAAA-HAAAAAAAAAAHHHHHHHHHHHHHH :D