I lived in Poland for 3 years. My first wife was Polish and from the countryside. It seemed that EVERY gathering, parties, weddings, birthday parties, etc. People sang "Sto Lat". It is an old very traditonal song. The melody is simple the words are easy. It means "One Hundred" and the gist of the song is wishing for the recipient to live 100 years. This a must play for any band at a Polish wedding.

From Wikipedia, "Sto Lat":

    Sto lat, sto lat,
    Niech żyje, żyje nam.
    Sto lat, sto lat,
    Niech żyje, żyje nam,
    Jeszcze raz, jeszcze raz,
    Niech żyje, żyje nam,
    Niech żyje nam!

This translates roughly into English as:

    100 years, 100 years,
    Let him/her live, live just for us.
    100 years, 100 years,
    Let him/her live, live just for us.
    Once again, once again,
    Let him/her live, live just for us,
    Let him/her live just for us!

Quick phonetics lesson:

ż is pronounced like the s "pleasure" or "measure"
sz is pronounced like "sh"
cz is pronounced like "ch"
j is pronounced like "y"
ch is pronounced something between "k" and "h". It is the same sound as the initial Ch/H in "Chunukah" or "Hanukah"

The song is easy to find on youtube, so you can hear the melody. It really is a simple song. It ought to be very, very easy to learn. You should be able to pick it up almost immediately.

If you want to surprise the bride, this ought to do it.

tim