Piano Sonata in B-flat ("Hammerklavier")
The slow movement has been described as "a mausoleum of collective sorrow."
Piano Sonata in A-flat
I saw Schiff play this in Vancouver. In the finale, Beethoven takes a common street song and turns it into something divine.
Piano Sonata in C Minor, Op. 111
In the final movement Beethoven invents jazz.
The Fugue has been described by pianists as "Aw, hell. Screw this, I give up."