Double Shot #1082

loads.in - Easy interface to worldwide speed checking for your website.
A Practical Guide to Using Signed Ruby Gems - Part 2: Heroku - With a patched buildpack. Alas, the signing system just really isn't robust enough to be useful yet.
stripe_event - Rails engine for integration with Stripe.
Upgrading Rails: Gems Extracted in Rails 4 - Thorough list from Andy Lindeman.