All blackjack is not the same!
The objective of blackjack is always the same--to beat the dealer. If
your cards total higher than the dealer's cards without going over 21
you win. Here is information on the standard game of blackjack:
http://entertainment.howstuffworks.com/blackjack.htm
When playing blackjack at a festival or other charitable event, the
standard rules are not used. "Charity Rule Blackjack" (or "Church Rule
Blackjack") has some very important differences that you should know
before you step up to the table. The charity rules increases the house
advantage from less than 1% to over 8%, so you are less likely to win
with charity rules (obviously, the church wants you to "donate" more
money).
The most important variations in the charity blackjack game are:
Natural blackjack: If you are dealt an Ace and a ten-value card you
have 21 known as a natural blackjack. With charity rules, you are paid
2 to 1 (meaning you get double what you bet)--this is better than
standard rules.
Pushes: If your hand ties the dealer's hand (called a "push"), no one
wins, and no one loses; you get your bet back. With charity rules, the
dealer wins all pushes; you always lose--this is much worse than
standard rules.
Charity rules can even differ from festival to festival so the rules
(related to natural blackjack, pushes, splitting, doubling down, etc.)
are usually posted on the walls around the blackjack tables.