How Do I Wake Up Early?

Sunday morning, the wife and I were supposed to go on a biking and kayaking trip, put together by some group, so we had to be there at a scheduled time. I, unfortunately, screwed up and couldn't fight my morning lethargy enough to get up early enough to make it to the meet up place in time.

I feel really dumb, too, because we were supposed to get out of the house later than I normally leave for work.

So anyone have any good tips on fighting morning lethargy when there's no good reason for having it? After all, I had gotten something like 7 or 8 hours of sleep. What's up with that?