Hrm... I must say, the theme song even today makes me cringe. That is, without a doubt, the girliest part of the show, even more so than Pinkie Pie. And her name is Pinkie Pie. What you should do is show them Wooden Toaster and The Living Tombstone
Well... The first episodes of the series didn't really get me hooked. The only way to actually like it is to keep going even though it seems lame at first. This is how I became a brony.
I watched it once and I didn't really care for it. It just seemed like an ordinary kids show. That's not to say it's bad or that I dislike it, I'm just not a fan.