One of the longest running shows on television, start with the 2005 reboot with Christopher Eccelston as the Doctor. Riding around time and space in the TARDIS, usually with a companion or two in tow, the Doctor fights monsters, solves conundrums and saves the day over and over again. With frequent changes in Doctors and companions and many guest writers, it can be very up and down, but when it is good, it is really good.