Given that this year's July 4 falls on a funky Wednesday, I actually had no special events that I planned to attend (either weekend before/after or day before/of) - but I will throw in my generic special events tips:
*Don't attend events famished! Have some vegetables, a whole fruit, or some protein -- that way you won't be starving during the event and risk devouring the whole table.
*Offer to bring a main/side dish - that way at least you know there's one thing that's "safe" to eat.
*Do the "plate rule" - fill up 2/3 of the plate plate with healthy veggies, and the remaining with whatever the heck you please. Helps portion control (of course, don't pile that 1/3 like a mountain
)
*Eat slowly, and take a breather/short walk before going for seconds- both will help you better evaluate how hungry/full you are. Also gives you an opportunity to burn a little bit of the calories you ate.