gistfile1.py

import clr
clr.AddReference("System.Management")
from System.Management import *
from System import Console

def EvLogEventArrived(sender, e):
  ##Get the Event object and display it
  for pd in e.NewEvent.Properties:
    Console.WriteLine("{0} = {1}", pd.Name, pd.Value)


scope = ManagementScope("root\\default");
q = WqlEventQuery();
q.EventClassName = "RegistryValueChangeEvent"
q.Condition = "Hive='HKEY_LOCAL_MACHINE' and KeyPath='Software\\\\RavnaAndTines'"+
 " and ValueName='my key'";
w = ManagementEventWatcher(scope, q)
try:
  w.EventArrived += EventArrivedEventHandler(EvLogEventArrived)
  w.Start()
  Console.ReadLine() ## Block this thread, keeping the app active
  ##and letting the event be handled on a system thread
  w.Stop()
finally:
  w.Dispose()