Drop in 2-Factor Authorization for your Rails app. You just need a Twilio account and you're set.

appt engine

Rails engine for managing Twilio phone numbers and SMS subscriptions

Minimalist form object implementation.

Provides support for validating, storing and retrieving phone, mobile, fax numbers with ISD code.

A person can have many email addresses, but this is not usually represented in applications. openopus/core/people creates the database structure, relations, and convenience functions for your application so you don't have to. Just connect your end user model, and away you go.

Adds a auto-formatting phone number field to RailsAdmin.

twilio_phone_verification is a gem for RoR which you can use to verify users' phone numbers

Delivery Method for Rails ActionMailer to send SMS messages using the Twilio API