This gist creates a application-only request, retrieving the newest tweet from the https://twitter.com/brianbondy/lists/stack-overflow-15 list. Can be used if you want to do application only things, described here: https://dev.twitter.com/docs/auth/application-only-auth simply by suppling another url to line 50.

Application-only request to Twitter

public static class GetStatuses
	{
		public static void Get()
		{
			// You need to set your own keys and screen name
			var oAuthConsumerKey = "";
			var oAuthConsumerSecret = "";
			var oAuthUrl = "https://api.twitter.com/oauth2/token";
			var screenname = "";

			// Do the Authenticate
			var authHeaderFormat = "Basic {0}";

			var authHeader = string.Format(authHeaderFormat,
				Convert.ToBase64String(Encoding.UTF8.GetBytes(Uri.EscapeDataString(oAuthConsumerKey) + ":" +
				Uri.EscapeDataString((oAuthConsumerSecret)))
			));

			var postBody = "grant_type=client_credentials";

			HttpWebRequest authRequest = (HttpWebRequest)WebRequest.Create(oAuthUrl);
			authRequest.Headers.Add("Authorization", authHeader);
			authRequest.Method = "POST";
			authRequest.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
			authRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

			using (Stream stream = authRequest.GetRequestStream())
			{
				byte[] content = ASCIIEncoding.ASCII.GetBytes(postBody);
				stream.Write(content, 0, content.Length);
			}

			authRequest.Headers.Add("Accept-Encoding", "gzip");

			WebResponse authResponse = authRequest.GetResponse();
			// deserialize into an object
			TwitAuthenticateResponse twitAuthResponse;
			using (authResponse)
			{
				using (var reader = new StreamReader(authResponse.GetResponseStream()))
				{
					JavaScriptSerializer js = new JavaScriptSerializer();
					var objectText = reader.ReadToEnd();
					twitAuthResponse = JsonConvert.DeserializeObject<TwitAuthenticateResponse>(objectText);
				}
			}

			// Do the timeline
			//var timelineFormat = "https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name={0}&include_rts=1&exclude_replies=1&count=5";
			var timelineFormat = "https://api.twitter.com/1.1/lists/statuses.json?list_id={0}&count=1";
			var timelineUrl = string.Format(timelineFormat, "32809390");
			HttpWebRequest timeLineRequest = (HttpWebRequest)WebRequest.Create(timelineUrl);
			var timelineHeaderFormat = "{0} {1}";
			timeLineRequest.Headers.Add("Authorization", string.Format(timelineHeaderFormat, twitAuthResponse.token_type, twitAuthResponse.access_token));
			timeLineRequest.Method = "Get";
			WebResponse timeLineResponse = timeLineRequest.GetResponse();
			var timeLineJson = string.Empty;
			using (timeLineResponse)
			{
				using (var reader = new StreamReader(timeLineResponse.GetResponseStream()))
				{
					timeLineJson = reader.ReadToEnd();
				}
			}

			Console.WriteLine(timeLineJson);
			Console.ReadKey();
		}
	}