Basically what I would do if my scheduled raid was canceled.
Usually, go to a different aspect of the game, be it leveling an alt, pvping, gathering mats, fishing, chatting with the guild, running dungons. At the time I was last in a guild with scheduled raids, I had plenty of time to do just those things, the raid gorup wasnt looking so hot on memebership and lots of times it just didnt go. This was much more annoying when I was working third shift and planning on raiding once I got up. I would get up about 15-30 minutes early just to be on time to the raid and see it had been canceled because few others wanted to raid.
Being on third shift wasnt really all that bad, but most of the time, I had a hard time getting to sleep, so getting up early was a really big deal.