What does Calvinism deny?
A lot of things, but most of what they deny is probably worth denying. Where I believe Calvinism denies a truth is that Calvinism by and large denies that God can and very well may use his Foreknowledge (even of what he foresees in a man's life) as a basis for election. The simple fact is that Foreknowledge is stated as a reason for election and the term "foreknowledge" is not theologically defined in the Bible.
Arminianism denies that God has the sovereign right to completely and unilaterally change a mans free will to make him incapable of rejecting the gospel message and incapable of falling away.
IMHO Arminianism puts too much emphasis on free will and Calvinism puts too much emphasis on God's determined will apart from his foreknowledge.
Next question.
What can you possibly do which God has not foreordained from before the creation?