Custom Made Batarangs!
Well the other day he not only surprised me with one fully functional throwing-star style batarang...
These things are so cool it's almost a shame to throw them around. I want to frame one of them or make an 'In case of emergency break glass' type display or something. But I have tossed one at a piece of wood and if you get that tip to land just right it sinks in pretty darn good.
I believe he said they were started from a piece of saw blade metal, so they are nice and sturdy considering the relative thinness of the metal. A template was drawn on and he ground them to size and gave the blades an edge (although he didn't sharpen them so I wouldn't cut myself open.) They were then painted with some high temp paint for durability. He said they were pretty simple to make and if you have a grinding wheel (I don't) you could make them quite easily and inexpensively.
So if you are so inclined - go for it!