GPS on bikes!

Why every biker should get one:
1) If you're left behind, you know which trail to use.
2) If you are too fast for the rest, you know which way to get back.
3) If you get chased by a tiger (not TigerHills) and drawn away from your group, you know how to get back on track (that is if you weren't eaten!)

Walkie Talkies

Sure is fun when the group is big and the terrain is lacking in technical traps to keep you occupied.

Auto Bike Lift

Real handy when used with a high 4-wheel drive. Also doubles up as a wet jersey hanger after rides!

Knives

Need we say more? IceCube's selection of knives are enough to ward of  tigers, pythons, bears?