Here's what I think you should do (and don't call me a nerd!
First, try to prepare yourself ahead of time, and read up on the subject before going to class. It lets you interact with the class, because you know what the prof will be talking about. In other words, it enables you to ask questions, and make relevant comments, (i.e., sucking up to the prof, and collecting valuable participation marks).
Second, sit in front of the class, like that, you'll double think about sleeping.
Third, bring a small snack. Eating keeps me awake. Like jus, muffin, cookies...
Lastly, it works for me, I register for morning classes. It's a bitch to wake up at 6am everyday, but I'm more awake at that time rather than after lunch...