Outdoor BBQs (although an actual BBQ enthusiast might prefer we say "grilling out") are common - family and friends together to cook burgers, hot dogs and ... Some communities will have July 4th parades and other community-wide celebrations, often with patriotic themes (marching veterans, police officers, and such). read more
You can expect lots of food. Usually it will be barbequed food; but people who have 4th of July parties usually have the same kind/type of food for the holiday. Also it may vary depending on ethnicity. Expect sun - wear sun screen. Also bring a cover up since it can get cool at night, depending on where you are. read more