➜  gist-1185322 git:(master) ruby --version
ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin10.8.0]
➜  gist-1185322 git:(master) ruby example.rb
/Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:21:in `scalar': expected SCALAR, SEQUENCE-START, MAPPING-START, or ALIAS (RuntimeError)
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:21:in `visit_Psych_Nodes_Scalar'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/visitor.rb:6:in `accept'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:16:in `block in visit_Psych_Nodes_Document'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:16:in `each'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:16:in `visit_Psych_Nodes_Document'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/visitor.rb:10:in `accept'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:10:in `block in visit_Psych_Nodes_Stream'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:10:in `each'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/emitter.rb:10:in `visit_Psych_Nodes_Stream'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/visitors/visitor.rb:11:in `accept'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych/nodes/node.rb:36:in `to_yaml'
	from /Users/myron/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/psych.rb:166:in `dump'
	from example.rb:4:in `<main>'