A very very simple example of a MonoGame/Xna Game class

Very basic MonoGame Game class

using BallZ.Levels;
using FarseerPhysics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input.Touch;

namespace BallZ
{
    public class BallZGame : Game
    {
        readonly GraphicsDeviceManager _graphics;
        private SpriteBatch _spriteBatch;
        private PrimitiveBatch _primitiveBatch;
        private Camera _camera;
        private GameLevel _gameLevel;

        public SpriteBatch SpriteBatch { get { return _spriteBatch; } }
        public PrimitiveBatch PrimitiveBatch { get { return _primitiveBatch; } }

        public BallZGame()
        {
            _graphics = new GraphicsDeviceManager(this)
                {
                    IsFullScreen = true,
                    SupportedOrientations = DisplayOrientation.Portrait, 
                    PreferredBackBufferWidth = 480,
                    PreferredBackBufferHeight = 800
                };

  		IsFixedTimeStep = false;
            Content.RootDirectory = "Content";
            TouchPanel.EnabledGestures = GestureType.Pinch | GestureType.Tap | GestureType.Hold;
        }
       
        protected override void Initialize()
        {
            _camera = new Camera(_graphics.GraphicsDevice.Viewport)
                {
                    Pos = new Vector2(_graphics.GraphicsDevice.Viewport.Width / 2f, _graphics.GraphicsDevice.Viewport.Height / 2f)
                };

            base.Initialize();
        }

        protected override void Update(GameTime gameTime)
        {
            _gameLevel.Update(gameTime, _camera);

            base.Update(gameTime);
        }
      
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.Black);
      
            _gameLevel.Draw(_camera);
    
            base.Draw(gameTime);
        }
    }
}