Somebody (generally a foreigner) who can't drive properly. Can be either a "cereal box" or a "cereal box driver".
The name comes from the fact that they probably got their licence out of a cereal box.
Argh! Flippin' cereal box!!! Learn how to drive!
a place u go to, to escape reality. no one else can enter your cereal box, only you!
brian: i went into my cereal box last night it was great!
shaun: huh? what are you high?!
brian: no dude you should go into your cereal box sometime its great!
brian: anything is possible when your-
brian: lalalalala in a cereal box!
shaun: ... poor ol brian. ok take him away boys.
(brian spent several years in the Cuckoo Puffs asylum, he was later found dead from suffocation inside a cereal box)