public static class DateProvider
    {
        private static DateTime? _frozenTime;

        public static DateTime Now
        {
            get { return _frozenTime ?? DateTime.Now; }
        }

        public static DateTime NowTruncated
        {
            get
            {
                return _frozenTime.HasValue
                           ? new DateTime(_frozenTime.Value.Year, frozenTime.Value.Month, frozenTime.Value.Day,
                                          frozenTime.Value.Hour, frozenTime.Value.Minute, _frozenTime.Value.Second)
                           : DateTime.Now;
            }
        }

        public static DateTime Today
        {
            get { return Now.Date; }
        }

        public static IDisposable FreezeTime(DateTime theFrozenTime)
        {
            _frozenTime = theFrozenTime;
            return new DisposableAction(() => _frozenTime = null);
        }

        public static bool IsFrozen()
        {
            return _frozenTime.HasValue;
        }

        public static void UnFreezeTime()
        {
            _frozenTime = null;
        }
    }
/// <summary>
    /// Better sytnax for context operation.
    /// Wraps a delegate that is executed when the Dispose method is called.
    /// This allows to do context sensitive things easily.
    /// Basically, it mimics Java's anonymous classes.
    /// </summary>
    public class DisposableAction : IDisposable
    {
        readonly Proc action;

        /// <summary>
        /// Initializes a new instance of the <see cref="DisposableAction"/> class.
        /// </summary>
        /// <param name="action">The action to execute on dispose</param>
        public DisposableAction(Proc action)
        {
            if (action == null)
                throw new ArgumentNullException("action");
            this.action = action;
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public virtual void Dispose()
        {
            action();
        }
    }