diff --git a/app/models/problem.rb b/app/models/problem.rb
--- a/app/models/problem.rb
+++ b/app/models/problem.rb
@@ -37,7 +37,9 @@
   end
 
   def self.find_available_problems
-    find(:all, :conditions => {:available => true}, :order => "date_added DESC")
+    find(:all, 
+         :conditions => {:available => true}, 
+         :order => "updated_at DESC")
   end
 
   # TODO: may try to optimize this using cache
diff --git a/app/views/main/list.html.haml b/app/views/main/list.html.haml
--- a/app/views/main/list.html.haml
+++ b/app/views/main/list.html.haml
@@ -37,6 +37,6 @@
   CodejomTimeout.updateProblemMessages();
   CodejomTimeout.registerRefreshEvent();
 
-= periodically_call_remote(:url => { :action => 'problems' }, :update => 'problem-list')
+= periodically_call_remote(:url => { :action => 'problems' }, :update => 'problem-list', :frequency => '3')
 
 
diff --git a/db/migrate/20100210012432_add_timestamp_to_problems.rb b/db/migrate/20100210012432_add_timestamp_to_problems.rb
new file mode 100644
--- /dev/null
+++ b/db/migrate/20100210012432_add_timestamp_to_problems.rb
@@ -0,0 +1,9 @@
+class AddTimestampToProblems < ActiveRecord::Migration
+  def self.up
+    add_column :problems, :updated_at, :timestamp
+  end
+
+  def self.down
+    remove_column :problems, :updated_at
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -9,7 +9,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20100209145331) do
+ActiveRecord::Schema.define(:version => 20100210012432) do
 
   create_table "announcements", :force => true do |t|
     t.string   "author"
@@ -84,16 +84,17 @@
   end
 
   create_table "problems", :force => true do |t|
-    t.string  "name",           :limit => 30
-    t.string  "full_name"
-    t.integer "full_score"
-    t.date    "date_added"
-    t.boolean "available"
-    t.string  "url"
-    t.integer "description_id"
-    t.boolean "test_allowed"
-    t.boolean "output_only"
-    t.integer "level",                        :default => 0
+    t.string   "name",           :limit => 30
+    t.string   "full_name"
+    t.integer  "full_score"
+    t.date     "date_added"
+    t.boolean  "available"
+    t.string   "url"
+    t.integer  "description_id"
+    t.boolean  "test_allowed"
+    t.boolean  "output_only"
+    t.integer  "level",                        :default => 0
+    t.datetime "updated_at"
   end
 
   create_table "rights", :force => true do |t|