A simple Redis-based session store for Redis. But why, you ask, when there's redis-store? redis-store is a one-fits-all solution, and I found it not to work properly with Rails, mostly due to a problem that seemed to lie in Rack's Abstract::ID class. I wanted something that worked, so I blatantly stole the code from Rails' MemCacheStore and turned it into a Redis version. No support for fancy stuff like distributed storage across several Redis instances. Feel free to add what you seem fit.
This library doesn't offer anything related to caching, and is only suitable for Rails applications. For other frameworks or drop-in support for caching, check out redis-store
gem install rails3-redis-session-store
See lib/redis-session-store.rb for a list of valid options. In your Rails app, throw in an initializer with the following contents and the configuration above:
YourApp::Application.config.session_store :redis_session_store, :db => 0, :expire_after => 10.minutes, :key_prefix => "your_app:session:"