gistfile1.txt

 $ irb
>> require 'active_support/core_ext/numeric/time'
=> true
>> 1.hour.ago
NoMethodError: undefined method `current' for Time:Class
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:68:in `ago'
	from (irb):2
>> require 'active_support/core_ext/time/calculations'
=> true
>> 1.hour.ago
ArgumentError: expected a time or date, got Mon Apr 18 17:23:07 -0600 2011
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:94:in `sum'
	from (irb):4:in `inject'
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:86:in `each'
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:86:in `inject'
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:86:in `sum'
	from /Users/rando/.rvm/gems/ree-1.8.7-2011.03@core/gems/activesupport-3.0.5/lib/active_support/duration.rb:69:in `ago'
	from (irb):4
>> require 'active_support/core_ext/time/acts_like'
=> true
>> 1.hour.ago
=> Mon Apr 18 16:23:12 -0600 2011