First and foremost, a book. If like me you believe in entertaining yourself then a great read (or two) is the way to go; Magazines are acceptable too... If you must.
Sun cream and insect repellent are vital = your older self will be full of thanks and the mosquitoes won't take you for an all you can eat buffet. On the same note don't forget to apply the latter at night especially if you're going somewhere tropical.
Tablet/Phone: Be sure to download a few games that don't require internet to play.
OBVIOUSLY.
DUH....
