I ran across this post on Facebook from Ben Andrews on May 6, 2016. It offers a good, solid response to those who want proof there is no god!
"Proof there is no god?
"How often have we encountered the Theists, when you ask for proof that god exists demanding that you 'prove' that God does not exist, and then get in a discussion who has the burden of proof instead of answering the question directly. Very frustrating.
"Here is the answer to that dilemma. Take the agnostic approach and begin the discussion with an 'I don’t know', an answer they can not ask you to 'prove' so they are still stuck with the burden of proof, before any other discussion takes place. Do not let them divert the debate, as they often do. Tell them repeatedly that no further discussion is possible until they prove their original claim. They will then quit or come up with some easily to defeat answers, such as 'look out the window', 'I had a vision' or 'I feel it in my heart'"