Mellonine is a Twimlet-style Twilio app that handles calls and texts.
It's not a purely stateless app, as SMS messages can set a token that voice calls can check to skip the passcode-dialing step and allow direct entry.
Use this form to construct the URLs to direct your app to. (For more in-depth documentation, view the source.)
NOTE: Some security systems may silence touch tones after a certain length. Also, Twilio thinks my apartment's '#' sounds like '3'. Keep these flaws / features in mind (you may wish to test your own system's behavior for such limitations).