diff --git a/lib/linguist/blob_helper.rb b/lib/linguist/blob_helper.rb
index 8050d37b..49fa3ca7 100644
--- a/lib/linguist/blob_helper.rb
+++ b/lib/linguist/blob_helper.rb
@@ -53,7 +53,7 @@ module Linguist
     #
     # Returns a content type String.
     def content_type
-      @content_type ||= binary? ? mime_type :
+      @content_type ||= (binary_mime_type? || binary?) ? mime_type :
         (encoding ? "text/plain; charset=#{encoding.downcase}" : "text/plain")
     end
 
diff --git a/lib/linguist/mime.rb b/lib/linguist/mime.rb
index 613e0914..e280209f 100644
--- a/lib/linguist/mime.rb
+++ b/lib/linguist/mime.rb
@@ -1,6 +1,10 @@
 require 'mime/types'
 require 'yaml'
 
+class MIME::Type
+  attr_accessor :override
+end
+
 # Register additional mime type extensions
 #
 # Follows same format as mime-types data file
@@ -33,6 +37,8 @@ File.read(File.expand_path("../mimes.yml", __FILE__)).lines.each do |line|
     mime_type.encoding = encoding
   end
 
+  mime_type.override = true
+
   # Kind of hacky, but we need to reindex the mime type after making changes
   MIME::Types.add_type_variant(mime_type)
   MIME::Types.index_extensions(mime_type)
@@ -72,8 +78,11 @@ module Linguist
         guesses = ::MIME::Types.type_for(ext_or_mime_type)
       end
 
-      # Prefer text mime types over binary
-      guesses.detect { |type| type.ascii? } ||
+      # Use custom override first
+      guesses.detect { |type| type.override } ||
+
+        # Prefer text mime types over binary
+        guesses.detect { |type| type.ascii? } ||
 
         # Otherwise use the first guess
         guesses.first
diff --git a/linguist.gemspec b/linguist.gemspec
index 12c7e765..b6dd8b5b 100644
--- a/linguist.gemspec
+++ b/linguist.gemspec
@@ -10,7 +10,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'charlock_holmes', '~> 0.6.6'
   s.add_dependency 'escape_utils',    '~> 0.2.3'
-  s.add_dependency 'mime-types',      '~> 1.16'
+  s.add_dependency 'mime-types',      '~> 1.18'
   s.add_dependency 'pygments.rb',     '~> 0.2.8'
   s.add_development_dependency 'rake'
 end
diff --git a/test/test_blob.rb b/test/test_blob.rb
index f62ad060..fe8dce62 100644
--- a/test/test_blob.rb
+++ b/test/test_blob.rb
@@ -33,6 +33,7 @@ class TestBlob < Test::Unit::TestCase
 
   def test_mime_type
     assert_equal "application/octet-stream", blob("dog.o").mime_type
+    assert_equal "application/ogg", blob("foo.ogg").mime_type
     assert_equal "application/postscript", blob("octocat.ai").mime_type
     assert_equal "application/x-ruby", blob("grit.rb").mime_type
     assert_equal "application/x-sh", blob("script.sh").mime_type
@@ -42,6 +43,7 @@ class TestBlob < Test::Unit::TestCase
 
   def test_content_type
     assert_equal "application/octet-stream", blob("dog.o").content_type
+    assert_equal "application/ogg", blob("foo.ogg").content_type
     assert_equal "application/pdf", blob("foo.pdf").content_type
     assert_equal "image/png", blob("foo.png").content_type
     assert_equal "text/plain; charset=iso-8859-2", blob("README").content_type
diff --git a/test/test_mime.rb b/test/test_mime.rb
index 454bee81..b18a6600 100644
--- a/test/test_mime.rb
+++ b/test/test_mime.rb
@@ -14,6 +14,20 @@ class TestMime < Test::Unit::TestCase
     # in mimes.yml. Its still useful to test even trivial cases since
     # MIME::Type's extension lookup may return multiple matches and we
     # only pick one of them. Please keep this list alphabetized.
+    assert_equal 'application/javascript', Mime.mime_for('.js')
+    assert_equal 'application/octet-stream', Mime.mime_for('.dll')
+    assert_equal 'application/octet-stream', Mime.mime_for('.dmg')
+    assert_equal 'application/octet-stream', Mime.mime_for('.exe')
+    assert_equal 'application/ogg', Mime.mime_for('.ogg')
+    assert_equal 'application/postscript', Mime.mime_for('.ai')
+    assert_equal 'application/postscript', Mime.mime_for('.eps')
+    assert_equal 'application/postscript', Mime.mime_for('.ps')
+    assert_equal 'application/vnd.adobe.air-application-installer-package+zip', Mime.mime_for('.air')
+    assert_equal 'application/vnd.oasis.opendocument.presentation', Mime.mime_for('.odp')
+    assert_equal 'application/vnd.oasis.opendocument.spreadsheet', Mime.mime_for('.ods')
+    assert_equal 'application/vnd.oasis.opendocument.text', Mime.mime_for('.odt')
+    assert_equal 'application/vnd.openofficeorg.extension', Mime.mime_for('.oxt')
+    assert_equal 'application/vnd.openxmlformats-officedocument.presentationml.presentation', Mime.mime_for('.pptx')
     assert_equal 'application/x-chrome-extension', Mime.mime_for('.crx')
     assert_equal 'application/x-debian-package', Mime.mime_for('.deb')
     assert_equal 'application/x-iwork-keynote-sffkey', Mime.mime_for('.key')
@@ -22,37 +36,19 @@ class TestMime < Test::Unit::TestCase
     assert_equal 'application/x-java-archive', Mime.mime_for('.ear')
     assert_equal 'application/x-java-archive', Mime.mime_for('.jar')
     assert_equal 'application/x-java-archive', Mime.mime_for('.war')
-    assert_equal 'application/javascript', Mime.mime_for('.js')
     assert_equal 'application/x-latex', Mime.mime_for('.latex')
     assert_equal 'application/x-ms-xbap', Mime.mime_for('.xbap')
-    assert_equal 'application/octet-stream', Mime.mime_for('.dll')
-    assert_equal 'application/octet-stream', Mime.mime_for('.dmg')
-    assert_equal 'application/octet-stream', Mime.mime_for('.exe')
     assert_equal 'application/x-perl', Mime.mime_for('.pl')
     assert_equal 'application/x-perl', Mime.mime_for('.pm')
-    assert_equal 'application/postscript', Mime.mime_for('.ai')
-    assert_equal 'application/postscript', Mime.mime_for('.eps')
-    assert_equal 'application/postscript', Mime.mime_for('.ps')
     assert_equal 'application/x-python', Mime.mime_for('.py')
     assert_equal 'application/x-ruby', Mime.mime_for('.rb')
     assert_equal 'application/x-sh', Mime.mime_for('.sh')
     assert_equal 'application/x-shockwave-flash', Mime.mime_for('.swf')
     assert_equal 'application/x-silverlight-app', Mime.mime_for('.xap')
     assert_equal 'application/x-supercollider', Mime.mime_for('.sc')
-    assert_equal 'application/vnd.adobe.air-applicationinstaller-package+zip', Mime.mime_for('.air')
-    assert_equal 'application/vnd.oasis.opendocument.presentation', Mime.mime_for('.odp')
-    assert_equal 'application/vnd.oasis.opendocument.spreadsheet', Mime.mime_for('.ods')
-    assert_equal 'application/vnd.oasis.opendocument.text', Mime.mime_for('.odt')
-    assert_equal 'application/vnd.openofficeorg.extension', Mime.mime_for('.oxt')
-    assert_equal 'application/vnd.openxmlformats-officedocument.presentationml.presentation', Mime.mime_for('.pptx')
     assert_equal 'application/xaml+xml', Mime.mime_for('.xaml')
     assert_equal 'text/cache-manifest', Mime.mime_for('.manifest')
     assert_equal 'text/html', Mime.mime_for('.html')
-    assert_equal 'text/x-nemerle', Mime.mime_for('.n')
-    assert_equal 'text/x-nimrod', Mime.mime_for('.nim')
-    assert_equal 'text/x-ocaml', Mime.mime_for('.ml')
-    assert_equal 'text/x-ocaml', Mime.mime_for('.sig')
-    assert_equal 'text/x-ocaml', Mime.mime_for('.sml')
     assert_equal 'text/plain', Mime.mime_for('.c')
     assert_equal 'text/plain', Mime.mime_for('.cc')
     assert_equal 'text/plain', Mime.mime_for('.cpp')
@@ -63,8 +59,13 @@ class TestMime < Test::Unit::TestCase
     assert_equal 'text/plain', Mime.mime_for('.hpp')
     assert_equal 'text/plain', Mime.mime_for('.kt')
     assert_equal 'text/x-logtalk', Mime.mime_for('.lgt')
-    assert_equal 'text/x-rust', Mime.mime_for('.rs')
+    assert_equal 'text/x-nemerle', Mime.mime_for('.n')
+    assert_equal 'text/x-nimrod', Mime.mime_for('.nim')
+    assert_equal 'text/x-ocaml', Mime.mime_for('.ml')
+    assert_equal 'text/x-ocaml', Mime.mime_for('.sig')
+    assert_equal 'text/x-ocaml', Mime.mime_for('.sml')
     assert_equal 'text/x-rust', Mime.mime_for('.rc')
+    assert_equal 'text/x-rust', Mime.mime_for('.rs')
     assert_equal 'video/quicktime', Mime.mime_for('.mov')
   end
 end