I'm not the first to say it but if you have Netflix, ignore everything else mentioned in this thread until you've watched Stranger Things. If you don't have Netflix, get it, then watch Stranger Things.
It's some of the best TV ever made. It's basically what you'd get if John Carpenter and Steven Spielberg got together in the mid-80s to make a 6 hour movie split into 8 parts. It's somewhere halfway between ET and A Nightmare on Elm Street.
Normally even the best TV series has at least one flaw: some bad acting, a slow episode or a plot-hole. I literally cannot think of a single flaw in Stranger Things. The attention to detail is incredible, down to the use of effects reminiscent of those used in the 80s films they're paying homage to. I really hope they make a second season and it lives up to the very high expectations set by the first.