Making Rails Go Vroom
The Great Ruby Shootout | Zen and the Art of Ruby Programming
assert_efficient_sql - O'Reilly Ruby
rails plugin that can detect inefficient queries in test cases
Ryan's Scraps: What's New in Edge Rails: Simpler Conditional Get Support (ETags)
ongoing · Tasty Rails ETags
Send files faster with X-Sendfile | John Guenin
New Nginx.conf with optimizations
sample nginx config for rails apps
InfoQ: EventMachine: Fast and Scalable Event-Driven I/O Framework
Coffee Powered » Fine tuning your garbage collector
That’s Not a Memory Leak, It’s Bloat | Engine Yard Blog
Client HTTP Caching in Rails - igvita.com
High Scalability - High Scalability - How Ravelry Scales to 10 Million Requests Using Rails
some more interesting data on Ravelry
Debugging memory leaks in Ruby
memory_profiler