gistfile1.rb

class Daterange
  include Mongoid::Document
  field :from, type: Date
  field :to, type: Date 
end

class Person
  include Mongoid::Document
  field :name, type: String
  embeds_many :dateranges                                                                                                                                                           
end

Person.delete_all
Daterange.delete_all

p = Person.create(name: 'myname')
p.dateranges << Daterange.create(from: Date.today, to: Date.today+1)
p.dateranges << Daterange.create(from: Date.today+5, to: Date.today+10)
p.save

puts Person.where('dateranges.to' => {'$gte' => '2010-11-01'}).first.inspect