diff --git a/README.md b/README.md
index 99a8617..6fc068b 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,12 @@ Cubist is a Cubism graphing sandbox.
 
 Enter Cube or Graphite expressions, get charts.
 
-Chart settings are chucked in local storage for later use.
+Charts are chucked in local storage for later use.
+
+## Features
+
+- server preferences and past expressions saved to local storage
+- comparison charts can be created by dragging one chart onto another ([screenshot](http://faulkner.io/t/screen2012-06-24at2.17.18AM.png))
 
 ## To install
 
@@ -31,6 +36,5 @@ $ export PORT=1234; cubist
 - live editing for existing charts
 - accept chart settings from query params
 - kill data polling when charts are removed
-- support for comparison charts
 - UI for removing old expressions
 - change typeahead into an autocomplete based on functions and metrics available
diff --git a/css/app.css b/css/app.css
index 56db9fc..6eba7f4 100644
--- a/css/app.css
+++ b/css/app.css
@@ -1,8 +1,12 @@
-.horizon {
+.horizon, .comparison {
   display:inline-block;
 }
 
 .chart-actions {
   vertical-align:top;
   display:inline-block;
+}
+
+.title {
+  display:block;
 }
\ No newline at end of file
diff --git a/js/app.coffee b/js/app.coffee
index 83b8bb0..a0ada12 100644
--- a/js/app.coffee
+++ b/js/app.coffee
@@ -25,35 +25,59 @@ class @Store
     graphite: ['carbon.agents.*.avgUpdateTime']
   charts: []
 
+# chart data sources
+@chart_data = []
+
 @context = cubism.context()
   .serverDelay(0)
   .clientDelay(0)
   .step(config.chart.step)
   .size(config.chart.size)
 
+chart_container = (charts, template, name='#charts') ->
+  data_id = (chart_data.push charts) - 1
+  container_id = _.uniqueId 'el'
+  container = $($(template).html())
+    .attr('id', container_id)
+    .data('chart', config.charts.length-1)
+    .data('data', data_id)
+  $(name).append(container)
+  container
+
 @add_chart = (chart, name='#charts') ->
   if chart.type == 'random'
     data = random 'random source #'+Math.floor(Math.random()*10000)
   else
     data = context[chart.type](chart.dsn).metric chart.expression
-  container_id = _.uniqueId 'el'
-  container = $($('#chart').html())
-    .attr('id', container_id)
-    .data('chart', config.charts.length-1)
-  $(name).append(container)
 
-  d3.select('#' + container_id).call (div) ->
+  container = chart_container data, '#chart'
+
+  d3.select('#' + container.attr('id')).call (div) ->
     div.select('.axis').call(context.axis().orient("top"))
-    div.datum(data)
     div.select('.horizon')
+    div.datum(data)
       .call(context.horizon()
         .height(config.chart.height)
         .extent(config.chart.extent)
         .colors(config.chart.colors))
-    div.select('.rule').call(context.rule())
 
-  # BREAK YOSELF
-  $('.title', container).prepend('<div>')
+  container.draggable revert: true
+  container.droppable
+    drop: (event, ui) ->
+      flash '<strong>Boom!</strong>  A comparison chart is born.', 'info'
+      primary = chart_data[$(@).data('data')]
+      secondary = chart_data[$(ui.draggable).data('data')]
+      add_comparison_chart primary, secondary
+
+@add_comparison_chart = (primary, secondary, name='#charts') ->
+  container = chart_container [primary, secondary], '#comp_chart'
+
+  d3.select('#' + container.attr('id')).call (div) ->
+    div.select('.axis').call(context.axis().orient("top"))
+    div.select('.comparison')
+      .datum([primary, secondary])
+      .call(context.comparison()
+        .height(config.chart.height))
 
 $('.create-chart').on 'click', (e) ->
   form = $(e.target).parents('form')
@@ -95,6 +119,3 @@ init_form = (name) ->
 init_form form for form in ['cube', 'graphite']
 
 add_chart c for c in config.charts
-
-context.on "focus", (i, e) ->
-  d3.selectAll(".value").style "right", (if not i? then null else context.size() - i + "px")
diff --git a/js/util.coffee b/js/util.coffee
index 08f5d94..d26e712 100644
--- a/js/util.coffee
+++ b/js/util.coffee
@@ -1,10 +1,16 @@
-@flash = (msg) ->
+@flash = (msg, type='error') ->
   # TODO: jadify!
-  $('.container-fluid:first').prepend('<div class="alert fade in">
+  $('.container-fluid:first').prepend('<div class="alert alert-'+type+' fade in out">
       <button type="button" class="close" data-dismiss="alert">×</button>
-      <strong>Oh shiii..</strong> '+msg+'
+      '+msg+'
     </div>')
 
+  # auto-remove non-errors
+  if type='info'
+    window.setTimeout () ->
+      $('.alert-info').alert('close')
+    , 4000
+
 # pulled from Cubism demo.  Tweaked to make horrible assumptions about there being a global @context.
 @random = (name) ->
   value = 0
diff --git a/package.json b/package.json
index 1806c88..781ce44 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,8 @@
     "d3": "2.9.4",
     "cubism": "1.2.0",
     "jquery": "1.7.2",
-    "underscore": "1.3.3"
+    "underscore": "1.3.3",
+    "jquery-ui": "git://github.com/jquery/jquery-ui.git"
   },
   "bin": {"cubist": "./bin/cubist"},
   "engines": {
diff --git a/views/index.jade b/views/index.jade
index aa6e9a2..17f3aeb 100644
--- a/views/index.jade
+++ b/views/index.jade
@@ -31,12 +31,20 @@ block content
         #charts
 
   script(type='text/html', id='chart')
-    .chart
+    .chart(draggable="true")
       .axis
       .horizon
       .chart-actions
         a.btn.btn-mini.close-btn
           i.icon-trash
 
+  script(type='text/html', id='comp_chart')
+    .chart
+      .axis
+      .comparison
+      .chart-actions
+        a.btn.btn-mini.close-btn
+          i.icon-trash
+
 block footer
   != js('app')
diff --git a/views/layout.jade b/views/layout.jade
index 3411296..dbad260 100644
--- a/views/layout.jade
+++ b/views/layout.jade
@@ -5,6 +5,7 @@ head
   meta(name="viewport", content="width=device-width, initial-scale=1.0")
   link(href='css/bootstrap.css', type='text/css', rel='stylesheet')
   link(href='css/app.css', type='text/css', rel='stylesheet')
+  link(href='n/jquery-ui/themes/base/jquery.ui.all.css', type='text/css', rel='stylesheet')
   block header
   
 body
@@ -16,6 +17,11 @@ body
   script(src='n/d3/d3.v2.js')
   script(src='n/cubism/cubism.v1.js')
   script(src='js/bootstrap.js')
+  script(src="n/jquery-ui/ui/jquery.ui.core.js")
+  script(src="n/jquery-ui/ui/jquery.ui.widget.js")
+  script(src="n/jquery-ui/ui/jquery.ui.mouse.js")
+  script(src="n/jquery-ui/ui/jquery.ui.draggable.js")
+  script(src="n/jquery-ui/ui/jquery.ui.droppable.js")
   != js('util')
 
   block footer