diff --git a/app/models/problem.rb b/app/models/problem.rb
--- a/app/models/problem.rb
+++ b/app/models/problem.rb
@@ -3,6 +3,13 @@
   belongs_to :description
   has_many :test_pairs, :dependent => :delete_all
 
+  named_scope :level, lambda { |level|
+    { :conditions => { :level => level }}
+  }
+
+  named_scope :unavailable, { :conditions => { :available => false }}
+
+
   validates_presence_of :name
   validates_format_of :name, :with => /^\w+$/
   validates_presence_of :full_name