These aren't always cardio workouts, but look at Sunday 060326, Friday 060324, or Thursday 060323 and see if this is what you're asking about. Personally, I found it hard to do CrossFit and a heavy lifting program simultaneously, but some people do. I still throw one of these in every once in a while, and it sure seems to do the trick.
Another thing I will do on a cardio day (if I have one) is to jump from machine to machine... ie: Row 1000 m, Bike for 10 min, Run for 10 min, Row 1000 m, then call it a day. It really makes it more interesting, and I find that it is more challenging as well. Hitting the rower for 1000 m at the end of a weights workout works as well.
Edit: You'll have to Google a bit...