No one has yet mentioned a staple of my childhood, the peanut butter and marshmallow fluff sandwich, affectionately known as the Fluffer-Nutter.

Here's a good one:
Spread one slice bread with PB
Spread the other with cranberry sauce
On the PB slice arrange chunks or slices of canned pineapple
Top with the cranberry sauce slice.

Also, PB and green chile jam, or PB and jalapeno jelly.

A PB and tabasco sandwich folded over is good in a pinch.