Play the "Dustbowl" map. Go to the MG36 battle pickup in the northwest area of the map near the water tower to find a couch named "The American Dream". It is actually a drivable vehicle that can hold up to four players.
Play the "High Tension" map and go to the second floor of the shopping mall. One of the stores is named "Ishimura", which is a reference to the "USG Ishimura" mining spaceship in Dead Space.
Play the "High Tension" map and enter the police station. You can find a few pink donut boxes on a folding table in the garage bay. When they are highlighted, press [Spot] to shout "donuts spotted!".