What is "head rush"

n. (alternative spelling of headrush English)

Head Rush (also billed as Head Rush Refresh in 2011) is a spin-off of the popular MythBusters show airing on Discovery's Science since it debuted in 2010.

Described by Discovery as a "commercial free hour of MythBusters mashups, hosted by Kari Byron", the show features about ten minutes of new material—experiments and quizzes presented by Kari, as well as TV celebrity and scientist appearances, pitching the idea that "science is cool"—interwoven in fifty minutes of material from MythBusters episodes.

These celebrity segments include "Cool Jobs In Science", which has featured other Science, Discovery, and TLC stars such as Dr. Michio Kaku (Sci Fi Science), Cake Bosss Buddy Valastro, Dr. G: Medical Examiners Dr. Jan Garavaglia, and each of the other four MythBusters.