This is fun way to pass the time and get some honor for pieces. Great way to get your guild working together.
You can go through the achievement list (Lord knows there are tons) and see what ones tickle your fancy. Do them or alone or with friends. Create a list and slowly work your way through it.
Farm for Something Special:
Farm for that special mount, pet or gear. Again, a great activity alone or with a group.
Help Your Lowbies:
Help get those lowbies leveled up in your guild. Do runs and show them how OP you are.
Hold special guild events as I've done in the past.
Get Gold Happy:
Find whats hot and make some gold before Cat comes. I'm sure there will be awesome loot and perhaps some special pets to purchase.
This is another activity we would often do. Do it in game and make it just Warcraft trivia or general trivia. Perhaps get rid of some items that are sitting in your g-bank as prizes
Nothing lifts the spirits like a dead horde. Get your guildies grouped up and head to a horde town and bring the pain. (unfortunately this one does not apply in reverse:P )
What you should be saying is "there is so little time and so much to do" before Cataclysm.
My goal is to farm/save 70k before Cataclysm. Presently I'm at 45k so I've still got a lot of work to do but if you continue to buy my old world mats, primal air for 30g per item and my terocone for 60g/stack, I'm well on my way hehe.