Pokémon: Diamond & Pearl
Nintendo DS Cameos

Wii

The main character has a Wii in their bedroom.

Submitted by TV Eye

Classic Pokémon Wallpaper

One of the wallpapers you can select for your menus shows a scene from Pokémon: Red & Blue, shown in the game's original graphics.

Submitted by TV Eye

A Winner Is You!

In Veilstone City, the clown that gives you the Coin Case says "A Winner Is You!"

This refers to a piece of poor English that first appeared in Pro Wrestling on the NES and later became an internet meme.

Submitted by TV Eye

Retro Pipe

One of the accessories that can be collected and used in contests is called the Retro Pipe. While it appears blue rather than green, the name suggests it is based on the pipes from the Super Mario series.

Submitted by kingmario

Game Freak

The Game Freak development team can be found at the Resort off Route 214. If you catch all of the Pokémon in the game, they award you with the Diploma.

Submitted by Smashchu