It's been 40 years since audiences were first asked "Who you gonna call …?" "Ghostbusters" was released in 1984, instantly becoming a hit, thanks to its funny, original script and catchy theme song.

Even Slimer makes a cameo! Jimmy Fallon and the Roots knew exactly who to call when it came time to perform their hilarious new rendition of the Ghostbusters theme song. The group opened their set ...