Start pestering him with stuff that he doesn't give a crusty about. I suggest randomly spouting off the capital cities of various far-flung nations that he's probably never heard of.

"Hey, did you know that the capital of Uzbekistan is Tashkent? No? Well, Tarawa's the capital of Kiribati, but it's actually very different from Uzbekistan. Have you ever been to Moldavia? I hear they make very good pies."