Here is the intro, a generic blues riff...

---4-----3-----2---0--3-3-2---------------------------------------------------
-------------------0--3-3-2---------------------------------------------------
-4---4-3---3-2---2-1--3-3-2---------------------------------------------------
----------------------2-2-1---------------------------------------------------
------------------------------------------------------------------------------
------------------------------------------------------------------------------

After you play that, you play the following section with a shuffle feel..

E
---------
---------
---------
---------
-2-2-4-4-
-0-0-0-0- X8

A
---------
---------
---------
-2-2-4-4-
-0-0-0-0-
--------- X8

E
---------
---------
---------
---------
-2-2-4-4-
-0-0-0-0- x8
                                                                              
B
---------
---------
---------
-4-4-6-6-
-2-2-2-2-
--------- X4

A
---------
---------
---------
-2-2-4-4-
-0-0-0-0-
--------- X4

E
---------
---------
---------
---------
-2-2-4-4-
-0-0-0-0- X4

B
---------
---------
---------
-4-4-4-4-
-2-2-2-2-
---------
Rinse hands. Wipe on pants. Repeat as necessary.

One thing you can do is record this with a tape recorder or a similar device, then improvise over it with the following Em Blues scale, which is based off of the Em Pentatonic scale:

------------------------0-3-
---------------------0-3----
---------------0-2-3--------
-----------0-2--------------
-----0-1-2------------------
-0-3------------------------