To post code samples I installed iG:Syntax Hiliter v3.5 for wordpress, which supposedly supports ruby. Now let's try it out:
PLAIN TEXT
RUBY:

def login

case @request.method

when :post

if @session['user'] = User.authenticate(@params['user_login'], @params['user_password'])

flash['notice']  = "Login successful"

redirect_back_or_default :controller => "moneyger", :action => "index"

else

@login    = @params['user_login']

@message  = "Login unsuccessful"

end

end

end

Excellent! ::-)