Core Dilemma

I've been wanting to incorporate core work for a while now. My swimming friends say it's critical, all the triathlete folks say it's critical. I get that it's important, just hadn't yet figured out how to add it to my schedule, especially now that it's gone from having loads of free time to missing workouts left and right to get client work done.

I've heard from various sources that Pilates is a good way to get in core work and I've been dying to try it. My excitement at learning my gym now offers a class was dashed when it turned out that it meets at the same time as my weight training class, which I'm lucky to get in half the time as it is.

With my days at the computer starting around 9am often stretching into 9... 10... 11 pm I quickly learned to take little breaks or my brain fries. My first experiment with this was taking 5 minutes every hour or so to do a restorative yoga pose. It did wonders the first time I tried it, and I think taking that extra time refreshed me to the point I was able to spend fewer total hours accomplishing the task.

I figured I can take this concept one step farther and include core work breaks during the day; problem is I don't actually know what to do. I know it's more complex than doing some crunches.

Here's what I've got: a balance ball, plenty of floor space, and some rather inadequate advice ("work on one-footed balance poses"). Can anyone out there give me a little more to go on?