arg....  You made me do it.  It sucks, but it works for basic types.
You must use it with an Array or Hash otherwise you get no headers:


class Object
	def to_html(value = self.to_s);
		return "<span class='RdBug_#{self.class.name}'>#{value}</span>"
	end
end

class String
	def to_html; super(self) end
end

class Symbol
	def to_html; super(':' + self.to_s) end
end

class NilClass
	def to_html; super('nil') end
end

class Hash
	def to_html
		html = "<table cellspacing=2 cellpadding=3
class='RdBug_Hash'><thead><td colspan=2
class='RdBug_HashHeader'>#{self.class}</td></thead>"
		self.each_pair do |k, v|
			html += "<tr><td
class='RdBug_HashKey'>#{k.to_html}</td><td>#{v.to_html}</td></tr>"
		end
		html += "</table>"
		super(html)
	end
end

class Array
	def to_html
		html = "<table cellspacing=2 cellpadding=3
class='RdBug_Array'><thead><td colspan=2
class='RdBug_ArrayHeader'>#{self.class}</td></thead>"
		self.size.times do |index|
			html += "<tr><td
class='RdBug_ArrayKey'>#{index}</td><td>#{self[index]}</td></tr>"
		end
		html += "</table>"
		super(html)
	end
end

variable = {
		"first"=> "1",
		:a23 => "second",
    "third"=> {
        nil => "inner third 1",
        "inner third 2"=>"yeah"
    },
		:values => [1, 2, 3, 4],
    nil => "fourth"
}

Then you can do:

<%= variable.to_html %>

To get output that looks very similar to the dBug stuff for Php.  I
used the styles that were at the link you provided, but I had to change
up the names to fit better:

<style type="text/css">
	table.RdBug_Array,table.RdBug_Object,table.RdBug_Hash,table.RdBug_String,table.RdBug_Symbol
{
		font-family:Verdana, Arial, Helvetica, sans-serif; color:#000000;
font-size:12px;
	}

	.RdBug_ArrayHeader,
	.RdBug_ObjectHeader,
	.RdBug_HashHeader,
	.RdBug_StringCHeader,
	.RdBug_SymbolHeader
		{ font-weight:bold; color:#FFFFFF; }

	/* array */
	table.RdBug_Array { background-color:#006600; }
	table.RdBug_Array td { background-color:#FFFFFF; }
	table.RdBug_Array td.RdBug_ArrayHeader { background-color:#009900; }
	table.RdBug_Array td.RdBug_ArrayKey { background-color:#CCFFCC; }

	/* resource */
	table.RdBug_Hash { background-color:#006600; }
	table.RdBug_Hash td { background-color:#FFFFFF; }
	table.RdBug_Hash td.RdBug_HashHeader { background-color:#009900; }
	table.RdBug_Hash td.RdBug_HashKey { background-color:#CCFFCC; }

</style>