seatcheck.rb

#!/usr/bin/ruby
require "rubygems"
require "scrapi"

url = 
"https://ui2web1.apps.uillinois.edu/BANPROD1/bwckschd.p_disp_detail_sched?term_in=120091&crn_in=43437"

seats = Scraper.define do
  array :numbers
  process "td.dddefault", :numbers=>:text
  result :numbers
end

result = seats.scrape(URI.parse(url))
remaining_seats = result[3].to_i

message = "[#{Time.now}] -- #{remaining_seats} seats"

if remaining_seats > 0
  require 'net/smtp'
  name = "your name"
  address = "email address"
  msg = <<EOM
From: #{name} <#{address}>
To: #{name} <#{address}>
Subject: CLASS OPENING

#{message}
EOM

  Net::SMTP.start("localhost") do |smtp|
    smtp.send_message msg, address, address
  end
end

File.open("~/seatcheck.log", "a") do |file|
  file << "#{message}\n"
end