Arguments against determinism?

I have been very interested in determinism lately and I have been wondering if there are any counter-arguments. I personally am more Compatibilist than anything, and I believe that even if determinism is true, free will can still exist if the definition is tweaked a little bit. I think that the only way to disprove determinism is to show that events can happen randomly with no cause. So my question is if anyone knows of any arguments proving that events can be spontaneous, that would in turn disprove determinism.