EventConsumer.cs

using UnityEngine;
using System.Collections;

public class EventConsumer : MonoBehaviour
{
    EventProvider ep;
    
    void Awake () 
    {
        ep = GetComponent<EventProvider>();
    }
    
    void OnEnable ()
    {
        ep.OnSomeEvent += HandleOnSomeEvent;
    }
    
    void OnDisable ()
    {
        // Remove our event handler when we're 
        // disabled to prevent handling the same
        // event multiple times
        ep.OnSomeEvent -= HandleOnSomeEvent;
    }
    
    void HandleOnSomeEvent () 
    {
        Debug.Log("SomeEvent handled!");
    }
}

EventProvider.cs

using UnityEngine;
using System.Collections;

public class EventProvider : MonoBehaviour 
{
    public delegate void SomeEvent();
    public event SomeEvent OnSomeEvent;
    
    void Update () 
    {
        if (OnSomeEvent != null) 
        {
            OnSomeEvent();
        }
    }
}