MgB2 is the superconductor with the highest critical temperature for a phonon-mediated superconductor. The superconductors with higher critical temperatures are the high temperature cuprates. The high temperature cuprates do not have a good theory to explain them. There is a good theory for phonon-mediated. This is used in the paper to describe a molecular architecture design of a room temperature superconductor. It will be hard to actually make it.
Andrei Mourachkine wrote a book in 2004 with ideas for making room temperature superconductors It involves various ways of bringing together molecular science and superconductivity. This is a link to a pdf copy of the book
Wikipedia entry on room temperature superconductors