5.Times(i => ...};

Times.cs

using System;

public static class Int32TimesExtension {
    public static void Times(this int numberOfTimes, Action<int> action) {
        for (int i = 0; i < numberOfTimes; i++)
            action.Invoke(i);
    }   
}

public class Program {
    public static void Main(string[] args) {
        5.Times(i => Console.WriteLine("hello {0}", i));
    }   
}