Create a site group in SharePoint 2010 using Client Object Model

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint.Client;
 
namespace COM
{
    class Program
    {
        static void Main(string[] args)
        {
            // siteURL is the string that contains the site URL 
            string siteUrl = "http://serverName:50000/sites/Testing";
            // ClientContext object is used to get the context for the SharePoint objects
            ClientContext clientContext = new ClientContext(siteUrl);
            Web web = clientContext.Web;   
        
            GroupCreationInformation groupCreationInfo = new GroupCreationInformation();
            groupCreationInfo.Title = "Custom Group";
            groupCreationInfo.Description="Custom group created using Client Object Model";
 
            User owner = web.EnsureUser(@"domainName\ownerName");
            User member = web.EnsureUser(@"domainName\userName");
 
            Group group = web.SiteGroups.Add(groupCreationInfo);
            group.Owner = owner;
            group.Users.AddUser(member);
            group.Update();       
            
            clientContext.ExecuteQuery();           
        }
    }
}