Less crazy but also very cool: the first coronary catheterization (insertion of a tube through a peripheral vein into the heart) was performed by doctor William Forssmann on himself. Forssmann's colleagues did not believe a coronary catheterization was possible without injuring the heart and possibly killing the patient, so he cathed himself, walked to imaging while cathed, and got X-rayed to prove the catheter was in his right atrium and that it could be done.