Virgina Creeper?
Sorry Clark Park, I wouldn't recommend English Ivy (Hedera Helix) as it is invasive in our area. I've seen it killing a lot of trees. I would recommend Virginia creeper. One of my rentals is a "brownstone" and it was growing on the walls and patio. It is pretty good at covering walls, and doesn't smother trees. As a plus, it turns pretty colors in Autumn. Of course, there will be the concrete visible in winter.
Stone Veneer
My favorite local nursery has 12inchX12inch bluestone squares for $5 a piece. I was surprised it was so inexpensive. You can probably order that or bigger sizes from a nursery upstate for about the same price. I'd do an online search for installation instructions. I wouldn't try to buy stone locally LOL I can imagine what they'd charge in Bklyn.
Artwork?
There are tons of talented fine arts graduates who are probably looking for a project. For several hundred, you can probably get a ceramic mural, fresco or gorgeous "trompe l'oeil." or "trampantojos" which is a mural w/ "depth" to "trick the eye." You may need to provide the materials, and ensure there's a topcoat suitable for the outdoors.