Since the simple_install branch lets me do this, added spoiler tags

include/boards/css/burichan.css

@@ -184,3 +184,6 @@ div.page_header ul li {font-weight: bold; text-align: left; padding-left:5px}
 div.page_header ul li ul {border:1px solid #000000;margin-left:-5px;padding-right:5px}
 div.page_header ul li ul li {font-weight: normal; text-align:left; position:relative;}
 div.page_header ul li ul li:hover { background: #C6DAF0; }
+
+span.spoiler {background: black; color: black;}
+span.spoiler:hover, span.spoiler:focus {color: white;}

include/boards/css/futaba.css

@@ -153,3 +153,6 @@ div.page_header ul li {font-weight: bold; text-align: left; padding-left:5px}
 div.page_header ul li ul {border:1px solid #000000;margin-left:-5px;padding-right:5px}
 div.page_header ul li ul li {font-weight: normal; text-align:left; position:relative;}
 div.page_header ul li ul li:hover { background: #C6DAF0; }
+
+span.spoiler {background: black; color: black;}
+span.spoiler:hover, span.spoiler:focus {color: white;}

include/boards/css/gurochan.css

@@ -136,3 +136,6 @@ div.page_header ul li {font-weight: bold; text-align: left; padding-left:5px}
 div.page_header ul li ul {border:1px solid #000000;margin-left:-5px;padding-right:5px}
 div.page_header ul li ul li {font-weight: normal; text-align:left; position:relative;}
 div.page_header ul li ul li:hover { background: #C6DAF0; }
+
+span.spoiler {background: black; color: black;}
+span.spoiler:hover, span.spoiler:focus {color: white;}

include/boards/css/photon.css

@@ -192,3 +192,6 @@ div.page_header ul li {font-weight: bold; text-align: left; padding-left:5px}
 div.page_header ul li ul {border:1px solid #000000;margin-left:-5px;padding-right:5px}
 div.page_header ul li ul li {font-weight: normal; text-align:left; position:relative;}
 div.page_header ul li ul li:hover { background: #C6DAF0; }
+
+span.spoiler {background: black; color: black;}
+span.spoiler:hover, span.spoiler:focus {color: white;}

str_format.py

@@ -213,6 +213,8 @@ WM_REPLACEMENTS = [
     (re.compile(r'\*\*([^\s].*?)\*\*'), r'<strong>\1</strong>'),
     (re.compile(r'\*([^\s].*?)\*'), r'<em>\1</em>'),
     (re.compile(r'`([^\n]*?)`'), r'<code>\1</code>'),
+    (re.compile(r'\[spoiler\]'), r'<span class="spoiler">'),
+    (re.compile(r'\[/spoiler\]'), r'</span><!--/spoiler-->'),
 ]
 
 WM_CODEBLOCK = [re.compile(r'^(    |\t)'), '<pre><code>', '', '\n',
@@ -308,6 +310,8 @@ TK_REPLACEMENTS = [
     (re.compile('</p>'), '\n\n'),
     (re.compile('<code>([^\n]*?)</code>'), r'`\1`'),
     (re.compile('</blockquote>'), '\n\n'),
+    (re.compile('<span class="spoiler">'), '[spoiler]'),
+    (re.compile('</span><!--/spoiler-->'), '[/spoiler]'),
 ]
 
 TK_CODEBLOCK = re.compile('<\s*?code>(.*?)</\s*?code>', re.S)