<object width="425" height="350"><param name="movie" value="http://www.youtube.com/v/3Qs9m_Wdr64"></param><embed src="http://www.youtube.com/v/3Qs9m_Wdr64" type="application/x-shockwave-flash" width="425" height="350"></embed></object>
EDIT: HTML must only work in sigs. D:
http://www.youtube.com/watch?v=3Qs9m_Wdr64