The Jerabek hyperbola is the isogonal conjugate of the Euler line. Some cool properties: [list] [*]The hyperbola intersects the circumcircle at E', the antipode of the reflection point of the Euler line (E). [*]Take the orthic triangle RST. The Euler lines of triangles ART, BRS, and CST are concurrent at the center of the hyperbola, which is on the nine-point circle. [/list]