At least an Otter Box !

http://www.otterbox.com/products/pda_cases/2600/

- Waterproof & airtight crushproof
- Lifetime unconditional guarantee
- You can leave it under your car's wheel ...



ps : i don't have one ... it's not a serious post ... don't try this at home ... and outdoor !
pps : it s a real photo of an outer box, but i don't know the model