Here's the basic progression in C. I typically capo it for different keys but I think 
in C sounds most like the original. Lovely song though.

Intro: C5 G5 A5 F5

(Progression 1:)
C5                       G5
It was a moment for the books
             A5
The calendar looked
              F5
just like the novels we had only skimmed through.
C5                    G5                          A5
So I circled out the dates that I'll skillfully waste.
    F5
For now that's going to have to do.

(Progression 1:)
C5                           G5                          A5
It was the brightest summer day, after we swam in the lake,
         F5
that you told me our luck is gonna end.
C5                  G5                              A5
So we better be concerned. We're where the subway turns.
          F5
We need a camera and some cash to spend.

(Progression 2:)
D5                  G5      A5                   C5
And our picturesque blame; we'll put it in IKEA-frames.
D5                        G5
Up on the wall it looks profound,
               A5                     F5
and reminds us Oslo is a small, small town. (Yeah)

(Progression 1:)
So it's night and we dive into a basement that's alive
with stupidity that melts into pairs.
But your good intent was clear when you split and left me here
to regret I left my high horse upstairs.

(Progression 2:)
And with the way I say goodbye
I could have ruined everything.
But I'll be seeing you around
because Oslo is a small, small town.

(Progression 2:)
I'm keeping myself calm
if just for the sake of staying warm.
So with my eyes fixed on the ground
I admitted Oslo is a small, small town. (Yeah)