I've always been fascinated by these hosts, as they combine elements of two of my favorite things- carnival barkers and public access television.  Unfortunately, I did not grow up watching any of these costumed characters introducing B-movies with bad puns and rubber masks.  I don't think there were any such programs available to me in small-town Minnesota.  
However, there was such a show in Minneapolis- "Horror Incorporated", which someone has done an incredibly thorough job blogging about right here.   It debuted in 1969 with a showing of Tod Browning's Dracula.  Here's the opening sequence: 
The show also had a modern incarnation which I, through my secret connections to the Twin Cities horror host industry, got to witness being filmed.  I appreciated their life-size Tor Johnson sculpture, and I even got to run the smoke machine!   Here's a sample of the show, which, if you need even more motivation to check it out, also includes someone in a gorilla suit:
American Scary turned out to be a fun look at horror hosts from all over the country, with interviews from many horror hosts with great names like 'Svengoolie', 'Dr. Sarcofiguy', and 'Crematia Mortem'.  There were also a number of other film experts such as Leonard Maltin, Bob Burns, and Joel Hodgson.  There was one guest that surprised me:  Neil Gaiman, and the reason for his inclusion was even more surprising: He had been a horror host himself! 
 It totally makes sense-  his stories often have a creepy, macabre edge, he always dresses in black, and he's got that nasal, British accent that's perfect for making you want to settle in on a cold autumn night for some classic scary movies.
He hosted for the Fox Movie Channel when they did a series called "The Thirteen Nights of Fright".  Now, thanks to internet magic, you can see him emerge from a coffin and do his horror host thing right here: