Safe and Cool: A Sunken Trampoline For Kids
Sunken Trampoline - worth a read before installing, love the grass covering
Dimensions for sunken trampoline
Crazily detailed instructions on how to build a sunken trampoline.
DIY Inground Trampoline Instructions
Sunken trampoline in landscaping, surrounded by mulch. Mulch is supposed to be a safer landing surface, since it has more give than grass on dirt in case the kids over-jump. It also blends into the garden area better.
Backyard play area
Sunken Trampoline Tutorial
Love this idea but would entail a heap of work so it is done right. Pinning it to consider.
The nitty gritty about building your own sunken trampoline.