Version 1.90.0 of GetText for Ruby has quite some memory leaks in its Rails support files. In my case, the memory Mongrel used increased by 1 MB with each request it served... Quite amazing that you don't really find someone else having the problem... Well there's at least a bug report on rubyforge...

Monkey-patching gettext.rb with the following code made things quite more relaxed:

  def bound_target(klass = self) # :nodoc:
    ret = nil