Thanks, guys. Actually, just holding down the power button for like 45 seconds did the trick. I just hadn't held the button down long enough. It wasn't a soft reset either. At least now somebody with the same issue might be able to try this.

I plugged my Nexus 7 into the USB wall charger for my phone at work for just a few minutes, and now it won't turn on. The battery level before I plugged it in was at 60% or so, so I know it has power. I press the power button for more than 4 seconds and I get nothing. Has anybody seen this problem before with any tablets?

It's rooted with the stock OS, so I can't send it back for warranty service if it won't turn on.