Artist: Yo La Tengo
Album: I Can Hear the Heart Beating As One (release date: April 22, 1997)
Song: Green Arrow

One of the more calm, soothing instrumentals off of I Can Hear the Heart...

Tuning: Standard

One guitar plays the following riff for pretty much the entire song:

|e---------------------------|
|B---------------------------|
|G-----3-----3-----3-----3---|
|D---1-----0-----------------|  
|A---------------1-----1-----|
|E---------------------------|

Variation: (takes place from about 3:20-3:30)

|e----------------------------|
|B----------------------------|
|G-----3-----------0-----0----|
|D---1-----0-3----------------|
|A---------------1-----1------|
|E----------------------------|

The other guitar plays several riffs, all of which include slides:

Intro riff:

|e---------|
|B---------|
|G---3/7---|
|D---------|  x4
|A---------|
|E---------|

Pre-chorus riff:

|e-------------------|
|B-------------------|
|G-------------------|
|D---3/12-10--3/12---|
|A-------------------|
|E-------------------|

Variation of the pre-chorus riff: (takes place at 2:33-2:55)

|e--------------------|
|B--------6---3/1/3---|
|G--------------------|
|D---3/12-------------|  x2
|A--------------------|
|E--------------------|

Chorus riff:

|e---3---3/6---6/5---3/1------|
|B------------------------3---|
|G----------------------------|
|D----------------------------|
|A----------------------------|
|E----------------------------|

Variation of the chorus riff: (takes place at 4:01-4:22)

|e---3---3/6---8---3---1---|
|B-------------------------|
|G-------------------------|
|D-------------------------|  x2
|A-------------------------|
|E-------------------------|

Additional riff which takes place at 4:22-4:44:

|e-----------------------------|
|B-----------------------------|
|G---6/3---3/6/3---1/3---6/3---|
|D-----------------------------|
|A-----------------------------|
|E-----------------------------|

That's it! Feel free to comment and/or post corrections if you find any.