Lakitu's intro
At the very start of the game's loading process, Lakitu is usually seen on his cloud holding a traffic light at the end of his fishing line. He occasionally has different objects at the end of the line, however. One of them is a small Cheep-Cheep (the fish), and another is a big Cheep-Cheep, one which broke Lakitu's fishing line. These are random and are a rarity.
Super Mario Kart remix
At the Title Screen, press Start once so that the the first menu is displayed (Start Game, Records, Options). When that's done, the normally-displayed game demo will not run. Wait for the tune's end, there will be a remix of a small portion of the original Super Mario Kart's title screen music.
// A mysterious character within the Banjo-Kazooie series was meant to star in his own N64 spin-off...