If I had nothing else to do and was independently wealthy, I'd sure spend some time trying to understand these two paragraphs from Wikipedia ;-)
Petr Hořava is well-known for his articles written with Edward Witten about the Hořava-Witten domain walls in M-theory. These articles demonstrated that the ten-dimensional heterotic E8 x E8 string theory could be produced from 11-dimensional M-theory by making one of the dimensions have edges (the domain walls). This discovery provided crucial support for the conjecture that all string theories could arise as various limits of a single higher-dimensional theory.
Hořava is less well known for his discovery of D-branes, usually attributed to Dai, Leigh and Polchinski, who discovered them independently, also in 1989. In 2009, Hořava proposed a theory of gravity that separates space from time at high energy while matching some predictions of general relativity at lower energies