Sometimes practical people are the hardest to shop for. You never know if they'll actually use what you're getting them. So instead of guessing what fun thing they might want, just go with the flow and get them something they'll actually use. This list is a great place to start.
1. Humangear Three Pack 3oz Gotoobs Squeeze Bottles
$29 on Amazon
A squeezable liquid transport tube for traveling or spending time outdoors with a no drip cap that actually works? What else could you ask for? Oh yeah, they're airplane approved too!