S = slap 
P = pop 
h = hammer-on 
  p = pull-off 
^ = bend 
~ = vibrato 
   / or  = slide up or down 

 Riff 1 
G|-----8---------------| 
D|--------10-8h10p8----| 
A|---6--------------11-| 
E|---------------------| 
     S P   P P       P 

 Riff 2 
G|-----------------------------|------------------|---------------------| 
D|-----------------------------|--------------2---|-----------------7---| 
A|--------------5--------------|------------------|---------------------| 
E|-0---0--3--5--------3---5--5-|--3---2--1--0---0-|-2--2--3---4---5-----| 
   S   S  S  S  S     S   S  S    S   S  S  S P S   S  S  S   S   S P 

How it's played: 
Riff 1 
Riff 2 x3 
Riff 1 
Riff 2 (without last note - D7) 

There's also these riffs that come up between scenes now and then. 
You can hear these in the sounds section of: www.best.com/~gilder/seinfeld/ 

 Riff 1 
G|----------------8----------------| 
D|-5-----6-----------10-8h10p8-----| 
A|--------------6--------------11--| 
E|---3-----4-----------------------| 
   P S   P S    S P   P P       P 

 Riff 2 
G|-----------------------| 
D|---------------------5-| 
A|--------------5--x-7---| 
E|-3--3-x-4-5-x----------| 
   S  S S S S S S  S S P 

 Riff 3 
G|------------------------| 
D|------------------------| 
A|----5^~~~---------------| 
E|-3---------7--5^~~~--3--| 
   S  P      S  S      S 

 Riff 4 
G|--------7-8-9^--------| 
D|-----------------------| 
A|-----------------------| 
E|-x-0--x----------2---3-| 
   S S  S P P P    S   S 

 Riff 5 
G|-------------| 
D|-5-----------| 
A|------7--5---| 
E|-----------3-| 
   P    P  P S