gistfile1.rb

# install the facebook_api gem first
require 'rubygems'
require 'facebook_api'

FacebookApi.configure do |config|
  config.api_key = 'API_KEY_HERE'
  config.secret_key = 'SECRET_KEY_HERE'
end

event_info = {:name => 'Event name', :start_time => Time.now.to_i}.to_json
session = FacebookApi::Session.new('SESSION_KEY_HERE', 'UID_HERE')
eid = session.call('Events.create', {:event_info => event_info, :session_key => 'SESSION_KEY_HERE'}, File.new('/path/to/image.jpg'))