Some 1.d4 players like to bring out the Trompowsky from time to time because they think players with the Black pieces get too comfortable playing their normal set-ups like the Slav or Queen's Gambit declined or Nimzo-Indian. Be ready for them, and show that their 'surprise' weapon isn't such a surprise to you!
This repertoire recommends an easy to remember set up that works in many variations aiming for ...Nf6 and pawns on d5 and c5 (most of the time), hitting variations where white takes with the bishop on f6, as well as lines where white delays or skips taking on f6 altogether.