I was looking at some kettlebell workouts yesterday online, and they look pretty good for working out your core. I like my Huge in  Hurry routine I'm doing now, but I'm looking for different options to hit the abs and core area on my off days.

Currently, I just do cardio on my non-lifting days with situps, etc. Do you think Kettlebells would be a good exercise in place of running to rip up the abs and build the core? If so, do you think I'd still get the rest I need from lifting on my off days if I did some kettlebell exercises?

It depends on what you do. You could so some kettbell swings in place of running, just make sure you do a lot of them if you are doing it for weight loss. I would not do things like snatches, presses, or get ups or it will interfere with your other exercise.

A word of caution though: you cannot do all things at the same time. This is something I struggle with. The greatest gains I have made (since the beginner phase - where everything works) were when I concentrated to exclusion on the "As Strong As You Look" series from Pavel Tsatsouline's book Beyond Bodybuilding. That was a good workout for my particular needs and most importantly, I didn't get distracted by trying too many new things.

What I might recommend if you are looking to try different things is take a week to try a variety of different programs, one day each, pick which one appeals to you most and stick to it for at least a month.

My brother lives for kettlebells. I appreciate his enthusiasm and all, but I do think keeping a set in his office and whipping them out and training midday is going a bit too far.

LOL, I would love to have workout gear at work.

He also installed a chin up bar in his office doorway. I do give him a A+ for dedication, I will say that.

Kettlebells...tractor tires...rocks....what do all these have in common? Weight! plain and simple. It is interesting that everyone is always looking for a "new" way to workout or get big. The science always remains the same...move/lift heavy weight + proper caloric/nutrient intake = Muscle. Look at the early bodybuilders Steve Reeves, John Grimeck, Dave Draper. All these guys had were basic weights and hard work. No bands, balls, machines etc...Free weights and cables if that's all they needed then it's good for me.