kjakub

2.hours.ago # => Fri, 02 Mar 2012 20:04:47 JST +09:00
1.day.from_now # => Fri, 03 Mar 2012 22:04:47 JST +09:00
Date.today.to_time_in_current_zone # => Fri, 02 Mar 2012 22:04:47 JST +09:00
Date.current # => Fri, 02 Mar
Time.zone.parse("2012-03-02 16:05:37") # => Fri, 02 Mar 2012 16:05:37 JST +09:00
Time.zone.now # => Fri, 02 Mar 2012 22:04:47 JST +09:00
Time.current # Same thing but shorter. (Thank you Lukas Sarnacki pointing this out.)
Time.zone.today # If you really can't have a Time or DateTime for some reason
Time.zone.now.utc.iso8601 # When supliyng an API (you can actually skip .zone here, but I find it better to always use it, than miss it when it's needed)
Time.strptime(time_string, '%Y-%m-%dT%H:%M:%S%z').in_time_zone(Time.zone) # If you can't use Time#parse