A Nice Walk through some old growth forest. (Note if you parked at the boat Ramp you will need to walk on the shoulder of a busy road for about 1/4 of a Mile. Alternatively you could park at the top of the hill and come down some hidden switchback.
Laughing Jacob's Falls is one of the last of the more urban waterfalls to be left untouched by nearby development. Though there is a large gated community situated just upstream, the canyon around the falls is still remarkably wild. Laughing Jacob's Creek, also known as Jensen Creek, flows over a sloping exposure of what looks like sandstone, dropping about 20 feet in a shady glen, before resuming a meandering course through an extremely brushy, steep walled canyon. The falls were formerly accessed from the Hans Jensen Youth Group area of Lake Sammammish State Park, but the trail which once was said to lead to the falls has long since disappeared.
Congratulations to alciato for FTF!