6-4

6-4 can refer to the following:
 * World 6-4 from various games
 * Level 6-4 from various games
 * Stage 6-4 from Donkey Kong for the Game Boy
 * Gleam Glacier 6-4 from Super Princess Peach
 * Room 6-4 from Mario vs. Donkey Kong 2: March of the Minis
 * Chapter 6-4 from Super Paper Mario
 * Area 6-4 from Mario vs. Donkey Kong: Mini-Land Mayhem!