all cats are silly, but what is the craziest thing your cats have ever done?
for mine...

Muffin...... when she...jumped? or climbed..to the top of a 7 or 8 foot bookcase! straight up! no levels, just whoosh!

Cassie..... well Im sure she will top this soon, but so far, its when she locked herself in the bathroom cupboard! seems she got in but couldn't get out (Im laughing as I type, remembering this) I heard slam! slam! she was trying to open the door to get back out and it kept shutting on her face! I went in there, opened the door and there was Cassie...hey mom, I can't get out!

as for the rest, nothing comes to mind YET,