I don't have to think too much about this one. My first answer is,"Reading!"
I am terrible at keeping track of how quickly time passes on a normal basis, but once I sit down with a book, I am a goner. I have never had to be forced to read. Ever. My wonderful mother taught me to read at age four, and I am so thankful! I see school kids who grudgingly suffer through book projects or thirty minute reading time, and I feel so bad. Because they have to be forced to read, they miss out on the purpose of reading. Reading is a way to take your mind somewhere it would not be able to go on it's own - it shows you new places, lets you meet new people, and teaches you anything you want to know. If you are a parent - please read to your kids! Ok, off my soapbox... :)
*Another activity that totally zaps my time (is more of a time waster, really) is Pinterest... but I hate to admit it! I have to be careful not to spend mindless hours scrolling through pages of pins, only to wake from a daze and realize that I have gone yet another day without fulfilling any of my responsibilities! I am determined that there is some sort of hypnotic power in scrolling down a screen - for me, anyway!
What makes you lose track of the minutes? How do you "zone out" and let the time fly by? Let me know in the comments!