C#

// this is the 1st project, SayHello.dll

public interface ISayHello
{
    public void SayHello();
}

// this is a 2nd project, Server.exe

using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;

...

// this is the server program that is a console application

static void Main(string[] args)
{
    // register a channel the client can talk to us on
TcpChannel channel = new TcpChannel(2600);
ChannelServices.RegisterChannel(channel);

    // create and publish a ServerSayHelloClass
    ServerSayHelloClass remoteObject = new ServerSayHelloClass();
    RemotingServices.Marshal(remoteObject, "Foobar.rem");

    // since this is a console app, wait for user input before exiting
    Console.ReadLine();
}

// make an ISayHello implementer. For this object to be remoted by reference, it must inherit from MarshalByRefObject
public class ServerSayHelloClass : MarshalByRefObject, ISayHello 
{

    public void SayHello()
    {
        Console.WriteLine("Hello!");
    }

    // return null if you want your remote object to live forever
    public override object InitializeLifetimeService()
    {
	return null;
    }
}

// this is a 3rd project, Client.exe

static void Main(string[] args)
{
    // connect to the server's published object
    ISayHello serverObject = (ISayHello)RemotingServices.Connect(typeof(ISayHello), "tcp://localhost:2600/Foobar.rem");

    // this will print something on the server!
    serverObject.SayHello(); 

    // if this is a console app, wait for user input before exiting
    Console.ReadLine();
}