"Walk on Water" (Lake Alster in Hamburg, Germany)
Vapur Anti-Bottle Folds down so it's easy to pack.
Open water swimming
These are hard to find, and very useful for swimmers. Frostfire Mooncode 1555 Portable Key Storage Security Lock: Amazon.co.uk: DIY & Tools
Avon Skin So Soft - best thing ever at keeping away the insects without melting the world. Oil based so it doesn't wash off.
Ghillie Kettle - super efficient way of making a brew, really really quickly. Top bit of kit (although a bit bulky). We won one!