For those who've never had Bubble Tea, or Boba as I and most I know call it, it's milk tea (which is just milk, tea, and some kind of sweetener) served with Tapioca Pearls, or Boba (Bubbles). It's usually sweet, comes in many flavors (Taro, Coconut, and Honey Oolong are my favorites), and you can usually choose stuff like Sweetness Level, Ice Level, and flavor of Pearls. Boba places also tend to serve unique slushes, milk caps, and other stuff that you probably won't be able to find anywhere else, so check out your local Boba place, it's worth the trip.
It's great, very very good drink. If I wasn't on a diet and live 20 miles from the nearest Kung Fu Tea, I would probably go every day. I usually go with 50% Sweetness Light Ice Taro Milk Tea.