- For a more comprehensive treatment, see the article on
Wikipedia.
Earl Grey tea is one of the most well known flavoured teas: using oil of bergamot oranges.
Many companies selling a variety of teas include Earl Grey and variants thereof - including with blue mallow (often called 'blue flowers') and lavender as additions. There are also Green Tea and Rooibos versions. Less strong versions are often called Lady Grey, Duchess Grey and similar.
It is named after the second Earl Grey, sometime British Prime Minister.
In popular culture 
Edit
Earl Grey is also a notable favorite of Star Trek's Captain Jean-Luc Picard. (See w:c:memory-alpha:Earl Grey tea.)
Results of the OED appeal for information on 'Earl Grey tea' is here [1].
