Long term I am raising the pipes so I have good ceiling height in the basement. Re: a smooth patch - I would rather have something that at least mimicks the tiles for the short term.

Cut drywall, and paint the entire ceiling. It's two years, not a lifetime.

The basement is a rental so it needs to look acceptable even in the short term.

Styrofoam sheets...glued up and painted...probably not notice the difference if you get them the same thickness as your ceiling tile.

Thanks erinsean. Where would I find these - ie are they easily available at a home improvement store?

"Styrofoam sheets...glued up and painted...probably not notice the difference if you get them the same thickness as your ceiling tile."

A light bulb will melt styrofoam, I think this may be the worst idea I have heard yet. Either cut drywall to mimic tile and make your own or drywall the hole encilada. You are not finding those tiles.

Interesting, as searching online I found styrofoam types tiles...

Styrofoam is a form of polystyrene, a highly flammable compound. I don't believe it is allowed by code in exposed interior locations unless covered by non-flammable materials. In a situation with a house fire, it would melt, emit toxic fumes, and increase the speed of the fire. Here is an illustration of how polystyrene reacts to open flame: Foam board flammability