From Wikipedia:
Uff da (can also be spelled uff-da, uffda, uff-dah, oofda, ufda, oofta or ufta) is an exclamation of Norwegianorigin that is relatively common in theUpper Midwesternstates of theUnited States. It roughly means "drats," "oops!" or "ouch!", especially if the "ouch!" is an empathetic one. In Norwegian Midwestern USA culture, "Uff Da" translates into: "I am overwhelmed." It has become a mark of Scandinavian roots, particularly for people from Minnesota.
http://en.wikipedia.org/wiki/Uff_da
I'm originally from Minnesota and one of my parents was of Norwegian origin. I often heard the expression "uff da!" from the older generation. I thought the id seemed appropriate for use on a lottery web site because of the number of times I buy tickets and win nothing, so in this case I'm using it to mean "drats!"