Watermelons are very common at 4th of July parties and seeds are very common in watermelons. It makes too much sense.
While spitting watermelon seeds may seem gross to some people, it is a traditional 4th of July activity with literally centuries of history. Besides, the kids are going to love it!
The Set Up: First, you are going to want a lot of watermelon seeds. Luckily watermelons have a lot of seeds so serve it at your 4th of July party during the seed spitting contest. That way the guests can get the seeds for the contest from the watermelon they are eating. Next, use large adhesive tape or a bag of flour, mark off a line on the ground which the guests will stand behind when spitting. Finally, make sure you have a tape measure handy.
The Rules: Each contestant gets three attempts at spitting a watermelon seed as far as possible. Track where the seeds land then measure and write down the longest attempt by each player. Once all guests have had their turn the person who spit the seed the longest distance is declared the watermelon seed spitting champion and awarded a prize.
A Prize for the Kids(optional): If you have kids playing you might consider awarding a separate prize for the youngsters or even for several different age groups.