personally, i want to see:
an april fool's day episode - where a prank michael pulls backfires horribly and jim and pam spend the entire day just messing with dwight.
an episode where michael decides that people need more perspective, and that everyone should switch jobs for a day. dwight as receptionist, jim as accountant, ryan as regional manager, etc.
and, an episode that takes place entirely out of the office where pam and jim hang out all day long and eventually jet off to vegas and get married.
the last one's just wishful thinking, but what do you guys think?