The first is a one day course in New York City on April 29th taught by Matt Pelletier and Francis Hwang, the founder of the NYC Ruby user group, humanist and author of, among other things, Lafcadio and MockFS. Francis has been building websites in Ruby for over 4 years now. Up until recently he was the primary developer for http://rhizome.org/. You can sign up here for $395.
For those on the other side of the pond, they are also offering a three day course in London , May 5 – 7 taught also by Matt as well as Dr. David Black of Ruby for Rails fame. That one is £1200 GBP and you can sign up here.