Warcraft_End of Lich King Blues
Every raiding guild encounters the end of the expansion blues. Many players lose interest, quit logging on, quit raiding, and so the guild tries to recruit more people to fill the gaps, killing progression and causing more people to take a break.
Luckily most 25 man guilds have enough people for 10 man heroic raids to fill in the time of the missed 25 man raiding experience. However this typically leaves 5 to 10 more raiders in the cold.
What can be done to keep interest in raiding during this time? Several things can be done for incentive and even raiding recruitment. First, on an off night have a "friends and alts run" where raiders bring their alts and friends, and friends of friends and tackle normal mode content. This can help discover new talent, plus it can be relaxing without having to perform on the edge.
Another tip is give extra DKP or other loot points to members who show up, even if the raid is canceled. If other people find out they are about to be passed on the loot list for item z, they may show up more.
Fiddle with the schedule. If you have attendance problems on glass chewing night, extend the raid lockout a day or two. Sucker them into showing up on farm night then give them glass chewing.
For those who don't raid(or do) and find themselves bored, there are still quite a few things to do. Farm for rare mounts and pets, max out all secondary professions, work on achievements, and make some gold. Remember, come Cataclysm, the world will be changing so some of those quest for loremaster may be gone. Some of those mobs that drop certain pets may become extinct.
Just because the expansion is ending doesn't mean its time to give up the game. Look around, there is still plenty to do.