My cat 'Red' also has a fascination for water, he used to jump in the shower when I got out and pounce on and then drink the rivulets of water heading for the drain! Then he grew out of that and started licking my feet when I got out of the shower. Now he's stopped doing that too, and he climbs on the bathroom sink when I'm shaving and gets in the way!
My theory about the attraction to pens etc. is that they roll around - as if alive?