http://rushfrisby.com/turboobject/

TurboObject.cs

using System;
using System.Collections.Generic;
using System.Dynamic;

public class TurboObject : DynamicObject
{
    private readonly object _defaultValue;
    private readonly Dictionary<string, object> _vals = new Dictionary<string, object>();

    public TurboObject()
    {
    }

    public TurboObject(object defaultValue)
    {
        _defaultValue = defaultValue;
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = _defaultValue;
        if (_vals.ContainsKey(binder.Name))
            result = _vals[binder.Name];
        return true;
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        if (!_vals.ContainsKey(binder.Name))
            _vals.Add(binder.Name, value);
        else
            _vals[binder.Name] = value;
        return true;
    }

    public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
    {
        var del = (Delegate)new Action(() => { });
        if (_vals.ContainsKey(binder.Name))
            del = (Delegate)_vals[binder.Name];
        result = del.DynamicInvoke(args);
        return true;
    }
}