These are few terms that will enhance your Oktoberfest experience:
aufstöin (v.): to donate a beer.
Batzerl (n.): small amount of something.
biddscheen (n.): please, can also mean “here you are” when someone is giving or serving something.
Brezn (n.): Bavarian pretzel. Aesthetically twined string of dough, baked to a pastry. At the Oktoberfest, the giant “Riesnbrezn” are especially beloved.
daessn (v.): to eat up
Deandl, Dirndl (n.): girl. The second term can also be used for a traditional Bavarian livery.
Dusl (n.): luck.
eihebn (n.): if you’re dizzy because of too much beer, you have to cling to something.
Fingahackln (n.): Bavarian sport. Two men hook their middle fingers and try to pull the opponent over the table. Popular activity at the Oktoberfest.
Goaßmaß (n.): Mixture of Coke, beer and cherry liqueur; has in fact nothing to do with Oktoberfest, something the Bavarians also vociferously verbalise: “Wos is’n des füra Schmarrn? Des arme Bier!” (What is that for an idiocy? Poor beer!)
Hoggableiba (n.): repeater, guest who doesn’t want to go home. Proverb: “Do hogga di do, di do oiwa do hogga.” (There they sit, who always sit there).
Noagerlzuzla (n.): person who drinks the last remainders from abandoned glasses, also used as a cuss.
ogschdocha (adj.): tipsy.
Schuaplattler (n.): Bavarian group dance for men, where you clap your hands on the thighs and the shanks.
zwieda (adj.): bad tempered, ill-humoured.
Feel free to use all your new terms in sentence!
For a complete listing of terms: http://www.oktoberfest.de/en/lexikon/