Here is a wonderful video demonstrating what cats can do:
I have one cat who goes into crazy zooming mode and runs from one end of the apartment to another and does what I call circuits around the living room. If she ate treats that were good for her, besides catnip, she might enjoy this.
Here's a photo from the web site from International Cat Agility Tournaments with some upscale equipment. The young man in the video made his own equipment, so it can be low cost.
Here I was just thinking it would be a good thing for high energy or tubby cats who are bored and need something to do. You know what it's like when a high energy cat is bored. They either bother you for attention, get into something they shouldn't or keep you up at night. Put the cat through the agility course a couple times and s/he should leave you alone for a while.