Hidden Warthog

On the Halo 2 level Outskirts, there is a hidden Warthog that you can find.

Finding it
To find the Warthog, all you have to do is progress through the level until you get outside the Hotel Zanzibar. A Warthog will drive up to your position. Get in it and drive all the way to the highway tunnel. When you get there, do not drive in. Instead, wait until an objective marker appears on the tunnel. When it appears, drive all the way back to the Hotel Zanzibar and look to the left of the exit of the hotel. There should be a Warthog on top of a platform, with tables surrounding it. You can drive it, but you cannot get it off the platform due to the gate surrounding the platform.

Trivia

 * The Warthog may or may not appear on Legendary difficulty.
 * The Warthog is the chaingun variant.