I have a rails application using the Facebook API. I've seen several different Ruby gems for integrating with Facebook, but they look dated.
Is it best to write low-level calls myself? Is there a decent and current gem available?
Have any of these gems changed recently?
I'm beginning a new project -- which gem should I use as of September, 2012?
The Koala Gem is the way to go.
These Railscasts from July will tell you all you need to know about interacting with the Social Graph in Ruby and in Rails (both are paid episodes):
#361: Facebook Graph API: Learn how to use the Facebook Graph API with the Koala gem to fetch data from Facebook and post content through a user. Here I delve into permissions, error handling, and more.
#363: Facebook Open Graph: This episode builds on last week's episodes and shows how to integrate Facebook further through the Open Graph protocol. You will also learn how to tunnel your local server and move Facebook communication into a background process.