Installing a trampoline

My wife and I wanted to get the kids a trampoline but didn't want some huge frame taking up the whole garden, also those net things that prevent them from flying off the edge are really ugly, so we copied our friends' idea of sinking the frame into the ground.
We were getting the garden landscaped and turfed so it was the perfect chance to dig a huge pit. Here's how it went:

First I put the frame together and marked the position of the legs on the ground

 Next I dug narrow trenches for the legs, testing the depth every now and then

 Then I got the frame into place and checked the level, adjusting as required

 When that was done I dropped the frame into the trenches (he makes it sound so easy) and dug out a bowl shape (actually it was a perfect parabola) to allow for bouncing child-feet, filling in the trenches with the earth

 The next day the guys came and turfed the lawn (marvelling at my engineering)

 All that was left then was to lay down a weed resistant membrane and fit the springs and the, err, middle bit

 And this is the finished result

And, of course, the best bit