diff --git a/README.rst b/README.rst
index 9543e63a0..724fa1fa3 100644
--- a/README.rst
+++ b/README.rst
@@ -1377,8 +1377,6 @@ For exemple, to grow 40 plump helmet spawn:
 
     growcrops plump 40
 
-This is a ruby script and needs the ruby plugin.
-
 
 removebadthoughts
 =================
@@ -1396,8 +1394,6 @@ you unpause.
 With the optional ``-v`` parameter, the script will dump the negative thoughts
 it removed.
 
-This is a ruby script and needs the ruby plugin.
-
 
 slayrace
 ========
@@ -1418,3 +1414,23 @@ after selecting the unit with the 'v' cursor:
 :: 
     rb_eval df.unit_find.body.blood_count = 0
 
+
+magmasource
+===========
+Create an infinite magma source on a tile.
+
+This script registers a map tile as a magma source, and every 12 game ticks
+that tile receives 1 new unit of flowing magma.
+
+Place the game cursor where you want to create the source (must be a
+flow-passable tile, and not too high in the sky) and call
+:: 
+    magmasource here
+
+To add more than 1 unit everytime, call the command again.
+
+To delete one source, place the cursor over its tile and use ``delete-here``.
+To remove all placed sources, call ``magmasource stop``.
+
+With no argument, this command shows an help message and list existing sources.
+
diff --git a/plugins/ruby/ruby.rb b/plugins/ruby/ruby.rb
index 5ae63ebfe..8c2c97969 100644
--- a/plugins/ruby/ruby.rb
+++ b/plugins/ruby/ruby.rb
@@ -38,15 +38,17 @@ module DFHack
                 @callback.call
             else
                 if year > @minyear or (year == @minyear and yeartick >= @minyeartick)
-                    @callback.call
                     @minyear = year
                     @minyeartick = yeartick + @ticklimit
                     if @minyeartick > yearlen
                         @minyear += 1
                         @minyeartick -= yearlen
                     end
+                    @callback.call
                 end
             end
+        rescue
+            puts_err "onupdate cb #$!", $!.backtrace
         end
 
         def <=>(o)
diff --git a/plugins/ruby/unit.rb b/plugins/ruby/unit.rb
index 04deee0e3..ebcf249da 100644
--- a/plugins/ruby/unit.rb
+++ b/plugins/ruby/unit.rb
@@ -6,9 +6,15 @@ module DFHack
         # with an argument that respond to x/y/z (eg cursor), find first unit at this position
         def unit_find(what=:selected, y=nil, z=nil)
             if what == :selected
-                if curview._rtti_classname == :viewscreen_itemst
+                case curview._rtti_classname
+                when :viewscreen_itemst
                     ref = curview.entry_ref[curview.cursor_pos]
                     ref.unit_tg if ref.kind_of?(GeneralRefUnit)
+                when :viewscreen_unitlistst
+                    v = curview
+                    # TODO fix xml to use enums everywhere
+                    page = DFHack::ViewscreenUnitlistst_TPage.int(v.page)
+                    v.units[page][v.cursor_pos[page]]
                 else
                     case ui.main.mode
                     when :ViewUnits
@@ -63,11 +69,11 @@ module DFHack
                 # current_job includes eat/drink/sleep/pickupequip
                 !u.job.current_job and 
                 # filter 'attend meeting'
-                u.meetings.length == 0 and
+                not u.specific_refs.find { |s| s.type == :ACTIVITY } and
                 # filter soldiers (TODO check schedule)
                 u.military.squad_index == -1 and
                 # filter 'on break'
-                !u.status.misc_traits.find { |t| id == :OnBreak }
+                not u.status.misc_traits.find { |t| t.id == :OnBreak }
             }
         end
 
diff --git a/scripts/magmasource.rb b/scripts/magmasource.rb
new file mode 100644
index 000000000..8525d51e0
--- /dev/null
+++ b/scripts/magmasource.rb
@@ -0,0 +1,66 @@
+# create an infinite magma source at the cursor
+
+$magma_sources ||= []
+
+case $script_args[0]
+when 'here'
+    $magma_onupdate ||= df.onupdate_register(12) {
+        # called every 12 game ticks (100x a dwarf day)
+        if $magma_sources.empty?
+            df.onupdate_unregister($magma_onupdate)
+            $magma_onupdate = nil
+        end
+
+        $magma_sources.each { |x, y, z|
+            if tile = df.map_tile_at(x, y, z) and DFHack::TiletypeShape::PassableFlow[tile.shape]
+                des = tile.designation
+                des.flow_size += 1 if des.flow_size < 7
+                des.liquid_type = 1
+                des.flow_forbid = true
+
+                mf = tile.mapblock.flags
+                mf.update_liquid = true
+                mf.update_liquid_twice = true
+
+                zf = df.world.map.z_level_flags[z]
+                zf.update = true
+                zf.update_twice = true
+            end
+        }
+    }
+
+    if df.cursor.x != -30000
+        if tile = df.map_tile_at(df.cursor)
+            if DFHack::TiletypeShape::PassableFlow[tile.shape]
+                $magma_sources << [df.cursor.x, df.cursor.y, df.cursor.z]
+            else
+                puts "Impassable tile: I'm afraid I can't do that, Dave"
+            end
+        else
+            puts "Unallocated map block - build something here first"
+        end
+    else
+        puts "Please put the game cursor where you want a magma source"
+    end
+
+when 'delete-here'
+    $magma_sources.delete [df.cursor.x, df.cursor.y, df.cursor.z]
+
+when 'stop'
+    $magma_sources.clear
+
+else
+    puts <<EOS
+Creates a new infinite magma source at the cursor.
+
+Arguments:
+ here - create a new source at the current cursor position
+        (call multiple times for higher flow)
+ delete-here - delete the source under the cursor
+ stop - delete all created magma sources
+EOS
+
+    if $magma_sources.first
+        puts '', 'Current magma sources:', $magma_sources.map { |s| " #{s.inspect}" }
+    end
+end