Or how two chars make the difference. A tale on my current project. While debugging a current app, I decided to start camping with $DEBUG = true. Suddenly, while loading a page, exceptions I have never seen started flowing in the console like the crocodiles in the river of the frogger game. This is because when $DEBUG is set to true, even handled/catched exceptions are printed to the console (but not the backtrace). This reminded me of "[href,:action,:src].map{|a|(h[a]=self/h[a])rescue 0". This is the line that escapes all urls to put them on the right path. Small instrumentation later, my page was generating 284! exceptions, with each a backtrace size of 65 in avg. By adding: 2 characters From: [:href,:action,:src].map{|a|(h[a]=self/h[a])rescue 0} To: [:href,:action,:src].map{|a|(h[a]&&=self/h[a])rescue 0} The exceptions dropped to 39 Finally, the poor man benchmark: [zimbatm at murray swarm]$ camping myapp.rb ** "myapp" app loaded ** Starting Mongrel on 0.0.0.0:3301 0.120000 0.010000 0.130000 ( 0.137303) 0.070000 0.010000 0.080000 ( 0.086835) 0.060000 0.010000 0.070000 ( 0.080585) 0.110000 0.010000 0.120000 ( 0.127002) 0.070000 0.020000 0.090000 ( 0.081667) [zimbatm at murray swarm]$ camping myapp.rb ** "myapp" app loaded ** Starting Mongrel on 0.0.0.0:3301 0.050000 0.010000 0.060000 ( 0.068349) 0.040000 0.010000 0.050000 ( 0.057737) 0.040000 0.010000 0.050000 ( 0.057360) 0.040000 0.010000 0.050000 ( 0.057386) 0.040000 0.010000 0.050000 ( 0.057580) Source : http://github.com/zimbatm/camping/tree/master Cheers, zimbatm