crazy_hash.rb

class Hash
  def method_missing(name, *args)
    key = name.to_s
    return self[key[0..-2]] = args.first if key =~ /=$/
    has_key?(key) ? self[key] : self.class.new
  end
end

params = { 'user' => { 'name' => 'Chris' } }

# getter
params::user # => {"name"=>"Chris"}
params::user::name # => "Chris" 

# setter
params::user::username = 'scharfie'