Basic and Beginner .NET LINQ

 class Program
    {
        static void Main(string[] args)
        {
            List<Car> ListOfCar = new List<Car>()
            {
                new Car {name = "Toyota"    , owner = "Alex" , model = 1992},  
                new Car {name = "Mitsubishi", owner = "Jeff" , model = 2005},  
                new Car {name = "Land Rover", owner = "Danny", model = 2001},  
                new Car {name = "BMW"       , owner = "Danny", model = 2006},  
                new Car {name = "Subaru"    , owner = "Smith", model = 2003}  
            };
            
            ///BASIC LINQ SINTAX
            ///
            IEnumerable<Car> QueryResult = from car in ListOfCar
                                           select car;

            foreach (Car car in QueryResult)
                Console.WriteLine(car.name);


            ///PROJECTION
            ///based on an existing object type
            IEnumerable<CarOwner> QueryResult = from car
                                                in ListOfCar
                                                select new CarOwner { owner_name = car.owner };
            foreach (CarOwner owner in QueryResult)
                Console.WriteLine(owner.owner_name);

            ///Projections using Anonymous Types
            ///type of the variable is unknown until. it�s assigned for the first time.
            ///
            var QueryResult = from car in ListOfCar
                              select new
                              {
                                  car_name = car.name,
                                  owner_name = car.owner
                              };
            Console.WriteLine("PROJECTION ANONYMOUS TYPE");
            foreach (var entry in QueryResult)
                Console.WriteLine(entry.car_name);

            ///REFINING DATA
            ///select by conditions
            ///
            IEnumerable<Car> QueryResult = from car in ListOfCar
                                           where car.name == "Subaru"
                                           select car;
            foreach (Car car in QueryResult)
                Console.WriteLine(car.name);

            ///ORDER BY
            ///
            IEnumerable<Car> QueryResult = from car in ListOfCar
                                           orderby car.model descending
                                           select car;
            foreach (Car car in QueryResult)
                Console.WriteLine(car.model + "," + car.name);

            ///GROUPING
            ///
            var QueryResult = from car in ListOfCar
                              group car by car.owner into carOnwerGroup
                              select carOnwerGroup.Key;
            
            ///JOINS
            ///join LINQ
            ///

            List<Car> ListOfCars = new List<Car>()  
            {  
                new Car {name = "Mitsubishi", owner = "Jeff" , model = 2005},  
                new Car {name = "Land Rover", owner = "Danny", model = 2001},  
                new Car {name = "Subaru"    , owner = "Smith", model = 2003},  
                new Car {name = "Toyota"    , owner = "Alex" , model = 1992},  
                new Car {name = "BMW"       , owner = "Danny", model = 2006},  
            };

            List<CarOwner> ListOfCarOwners = new List<CarOwner>()  
            {  
                new CarOwner {owner_name = "Danny", age = 22},  
                new CarOwner {owner_name = "Jeff" , age = 35},  
                new CarOwner {owner_name = "Smith", age = 19},  
                new CarOwner {owner_name = "Alex" , age = 40}  
            };
            var QueryResult = from car in ListOfCars
                              join carowner in ListOfCarOwners on car.name equals carowner.owner_name
                              select new
                              {
                                  name = car.name,
                                  owner = car.owner,
                                  owner_age = carowner.age
                              };
            foreach (var entry in QueryResult)                
                Console.Write(entry.name + "," + entry.owner + "," + entry.owner_age);




            Console.Read();
        }
    }

    class Car
    {
        public string name { get; set; }
        public string owner { get; set; }
        public int model { get; set; }
    }
    class CarOwner
    {
        public string owner_name { get; set; }
        public int age { get; set; }
    }

full article http://net.tutsplus.com/tutorials/asp-net/net-linq-from-scratch/