While they're absolute LIFE SAVERS in the summer months (or, if you live in the South like me, 11 months out of the year), A/C window units are pretty much hideous. But, cooler temperatures bring the opportunity to hide or disguise that window A/C during the winter, and it's a small tweak that will dramatically upgrade a room's look.
An Easy and Elegant Option → Prop art in front of it!
The A/C window unit hiding idea in Alex Fitzgerald's small West Village apartment is so simple that it hardly can be categorized as a tip — it's a no-brainer when you see how easily it covers the A/C. A simple canvas piece that's a little larger than the unit leans up against it when not in use. No holes, no drills, basically the smallest amount of effort.
In Alex's apartment, he's lucky to have the radiator act as a shelf for the canvas to rest on. But if you don't have a convenient surface already underneath your window unit, see if there's an opportunity to move an existing console table, bookshelf, etc. under your window unit to give you a surface to set art on.