This is a song The Band would open or close their concert with. It was originally done by Marvin Gaye.
(Standard Tuning: E B G D A E)
The song is simple:
[ Tab from: http://www.guitaretab.com/t/the-band/64531.html ]
G C Bb G
E|--3--------------3-|
B|--3--5-5--5---3--3-|
G|--4--5-5--5---3--4-|
D|--5--5-5--5---3--5-|
A|--5--3-3--3---1--5-|
E|--5--------------3-| Repeat this throught the entire song.
Solo over these chords in C minor.
Improvise around those chords to make it more interesting.
Here's a riff to get your started.
E|---------------------|
B|---------------------|
G|-----3--3h5~-5p3-----|
D|--/5---5---------5~~~|
A|---------------------|
E|---------------------|