Bored!

I need a tip: I get SO bored when I run. It seems I have heard all the songs on my iPod a million times, and I get really frustrated with that. When I run alone, I really sell myself short because it's extremely boring to listen to your feet hit the pavement (or even worse, the treadmill) for an hour. What do I do? I haven't been getting a great workout because I'm always stopping to change my music, or adjust my headphones, or simply to talk myself out of turning back and going home because I am bored. Maybe I am not challenged enough, maybe I need some goals to accomplish so it feels like I'm not running without purpose. Or, maybe just some music suggestions....