Somerset County 4-H Fair

This annual event, always on a W-​Th-​F in mid-​August, is an area tradition. Unlike other county fairs, there’s never a charge to get in or park. The food tent is 100% local non-​profits (fire departments, churches, Boy Scouts, etc.), so you know the «profit» is going to a good cause. A not-​insignificant chunk of the food revenue goes to the 4-​H and helps fund this very expensive event.
There are no rides, but you can visit politicians at various tents and stands.
The emphases are agriculture and education. You’ll see cows, chickens, goats, cats, dogs, horses, and a host of other critters. There are also bands and stuff for the kids like operating a back-​hoe (really); the Children’s Museum exhibit; model trains, cars, and planes; the Rutgers Extension service; clubs; etc. There are commercial displays for mulch, basement waterproofing, etc., but you don’t feel like it’s a hard-​sell trade show by any stretch.
If the weather is dry, there is some parking at the site, though parking at Raritan Valley Community College (a few miles away, but with free bus shuttles) is recommended. If it rains, they quickly curtail or close on-​site parking and it may take longer for the shuttle service (which is now air-​conditioned buses!).
The smart move is to take off a day from work if you can, and spend a few hours. Evenings are far more crowded, in addition to dealing with rush-​hour traffic in general.
FULL DISCLOSURE: My church operates a stand under the gigantic food tent, and I spend a lot of time there volunteering.