Alright, I am a bit prejudiced about Parky's Hot Dogs since I've been eating them for over 50 years, but even the current reviews I've read about this place on other websites seems to at least semi-agree with me about this place.
Actually when I was growing up in Berwyn (suburb of Chicago) there were actually two Parky's Hot Dog Stands. The one here in Forest Park and the original (where I went) in Berwyn.
The original owners founded Parky's in 1949 a few years before I was born and the second owners bought them in 1995 (I found that out in my visit today). Alas the one in Berwyn has changed like the neighborhood and is now under a different name and serving Mexican food and I'm not sure if they are even the same owner. But fortunately Parky's survives in this location which really has the same look and feel as the original.
A little side note of interest. One of the first 10 McDonald's was built in Berwyn when I was growing up just down the street from Parky's and for a couple of years the lines at Parky's were just as long if not longer then McDonald's.
Favorite Dish: Take a close look at the pictures and you can see the menu of Hot Dogs, Italian Beef and Sausage. I think the Italian Beef and Sausage was an addition in the 1960's or 1970's but since the only thing I've ever ordered was the Hot Dog and Fries I couldn't tell you about anything else on the menu.
The Hot Dog and Fries come together in a double paper bag to absorb the grease from the fries. The fries are what people always come back for. You get a huge helping of thin cut fries which are usually very dark in color and loaded with salt. They will ask now if you would like salt and if you do they give you a very generous sprinkle. The hot dog is steamed on a steamed bun and comes with whatever you would like, but if you are a true Chicagoan you will not ask for ketchup.
A lot of Hot Dog stands in Chicago use Vienna All Beef Hot Dogs while Parky's uses David Berg which is another local brand.
You can also order just a bag of fries as one lady did while I was sitting there eating my lunch. Eat the fries right when you get them while they are nice and hot.