What have you been up to
"What have you been up to today?" is a question that asks what you have done all day, like work or leisure activities, in the past tense.
Q: "What have you been up to today?"
A: "I was at work until 5:00pm, and then I went to the store to pick up some milk."
A: "I was at work until 5:00pm, and then I went to the store to pick up some milk."