Okay. It's old climbing rope. It's frayed, it's dirty, it's been used hard and put away wet a few times. You don't want to trust your life to it anymore.
It's still good rope. Lots of possibilities here. Specially if it's free. Or, you know, for a few beers you'd give your buddy anyway, cause he's your buddy.
For a bow or stern line
A perimeter line
To tie stuff to/in your boat
To make a cargo net
To hang stuff in your garage
For your drag bag
To hang stuff in trees in camp
To anchor your oars in the sand for the volley ball net
And in a pinch, to make a tree swing