Additional problems:

cannot ping gems.rubyforge.org

The test script:
require 'socket'

hostname = ARGV[0]
puts "Making socket to #{hostname}"
sock = TCPSocket.new(hostname, 80)
mesg = "GET / HTTP/1.1\r\nHost: #{hostname}\r\n\r\n"
puts "writing to socket #{hostname}: " + mesg
sock.write mesg
puts "Wow, no hang!"

hangs on www.google.com

Anyway, my internet connection seems to be ok...