My shirt that has a picture of Einstein smoking his pipe, but instead of smoke the Milky Way is coming out of the pipe.
Being a teenager in California, the most common response I get is "Woah, man. That shirt is trippy". To which I always reply "Yeah, Einstein's been smoking a bit too much Science".
I also used to have an antique hidden sword inside a cane, Which was solid brass on the outside. I say used to because I broke it.