My grandfather (my dad's dad) owned a lake house on Lake Hopatcong, NJ. At least once a month, usually more, between April and September, our family would pile into the station wagon and drive to visit him.
Us kids (me, my older sister, and a handful of cousins) would go swimming (usually preceeded by a running leap off the end of his dock) while the adults would sit on lounge chairs in the back yard, keep an eye on us, and get mildly plastered on martinis, scotch, and the like.
Occasionally, my grandfather would take us out for a boat ride. Of course, all us kids would have to wear live jackets, so we would wind up with really odd tan lines.
I also used to go fishing off the side of the dock. I never caught anything bigger than a sunfish, but I sure had fun trying.