Colwith Force, Little Langdale is a beautiful, short easy walk to some amazing cascades and a magnificent waterfall. Especially after heavy rainfall. The walk is less than 0.5 miles in total, there and back, and could easily be incorporated into other walks, if you fancied something longer (Elterwater to Skelwith Bridge for example).
There is limited parking, although it is free. We found a small lay-by just before Colwith Bridge, at GR331030 on OS map OL7. There are also a couple of spots just after the bridge on the left. So get there early to avoid disappointment!
Follow the clear footpath straight up to the falls. The path itself is fun, with dead trees to climb on, and some rocks to scramble over. There are two viewing points for the falls, the lower one being the better one in my opinion. Hold on tight to your kids, as there are steep drops.
This video shows the last half of the walk, and the falls themselves:
If you walk to the upper viewpoint, you can see the top cascades before the water goes over the falls.
Return the way you came to the start of the walk. And if you fancy something to eat, the Three Shires Pub in Little Langdale serves fantastic food, and is only a short drive away.