Akina Minami cameos
Check out Metal Gear Solid 4's easter eggs and Hideo Kojima's love for Japanese fashion model Akina Minami becomes obvious. During the Mission Briefings on the Nomad, you can guide the Metal Gear Mk. II or III to the television and press R1 to turn on the remote control on top of the table. It gets a bit tricky to aim since the table is taller than the Mk. II/III, but proper execution reveals Akina on the television in bra and panties and other outfits that aren't quite mother-approved.
In Vista Mansion in Act 2, you can shoot down one of the portraits to reveal an Akina Minama poster.