I'm not exactly sure what you mean by "funny ways," which sounds like there are people out there who try to prove God doesn't exist by covering themselves in whipped cream and going roller-blading naked through a movie theater. I'm only aware of "not funny" reasons people have for doubting God's existence, which are the same reasons people have for doubting the existence of Santa, Bigfoot, the Tooth Fairy, the Easter Bunny, Vampires, Werewolves, Dragons, Unicorns, Elves, Goblins, Faeries, etc: there IS NO EVIDENCE for any such creatures.
I'm operating under the working assumption that you don't believe in werewolves. And the REASON you probably don't believe in werewolves is that there isn't any evidence that werewolves exist...which you probably think is a valid reason for not believing in them (and you'd be right). The existence of God is no more self-evident than the existence of werewolves, so maybe you should tell us why you think one non-belief is funny while the other one is valid.