Normally, I'd just add a comment or post a link, but I'll post the instructions again.  The page with kitty pictures and examples is here.

I've had several requests for this pattern. It's incredibly easy and you can modify it really easily to fit what you want to do. To standardize things, I'm going to write the pattern and instructons out for an afghan made up of 5 block stripes like the one in the picture. You can easily make it longer or shorter depending on the number of block stripes you want. 3 would be good for a lapghan and 4 would work well for a kid's blanket.

You will be crocheting with 2 strands of yarn, so the afghan will come out much thicker. I recommend not working on one of these in the summer unless you happen to spend LOTS of time in air-conditioning -- they tend to warm your lap up really fast. :) (They are great for Midwestern winters.) An advantage of 2 strands of yarn and a larger hook is that you can actually crochet by feel once you get the rhythm down. I find that I can get 6" done during the 2 hours between gas stops on car trips and as much as 3" done during a high school basketball game. :) Instead of fringing (which is a pain), you'll be edging which looks nicer and covers a multitude of mistakes. :)

Colors
I've made 5 of these afghans in the last few years and my recommendation is this: pick 2-3 colors to work with. You can do black with two different shades of green, for example or you can do your favorite team colors. Whatever your master color (MC) is (the one in which you will crochet 3 of the stripes), make that the color you use for edging. You can also mix 2 different colors for your alternate color (AC). It has the effect of a varigated yarn. If you choose to work with 3 colors, substitute one of the AC stripes for a BC stripe. (For example, MC = black, AC = dark green, and BC = light green.)

Abbreviations
Ch: chain
Dc: double crochet
MC: master color
AC: alternate color
EC: edging color

What You Need
+ 12 skeins of Red Heart Supersaver yarn: 8 skeins of MC, 4 skeins AC
+ N hook
+ a safety pin
+ lots of patience
+ time where you're just sitting (watching TV, movies, sporting events, or scenery on a car trip)
+ cats to test the nap quality of the afghan (optional)

Pattern
Divide your yarn into pairs: MC1, AC1, MC2, AC2, MC3, and EC. Ch 150 with 2 strands of MC1.
1st row: Dc in the third chain from the end and continue dc until the end of the row. Ch 2.
2nd row: Dc in each stitch across the row. Ch 2.
Repeat until you run out of MC1. (Gauge how much yarn you have. If you can't make another row, stop with the row you've finished.) Tie off.
Attach AC1 and make 2 loops around your hook. Dc in every stitch across row. Ch 2.
Repeat until you run out of AC1.
Repeat with MC2, AC2, and MC3.
To edge, mark the place you're starting with the safety pin and do with EC as you did with AC1, MC2, AC2, and MC3. When you get to the corner, make 3 double crochets in the corner stitch. Continue until you've come back to the place you marked with the safety pin. When edging, double crochet over the places you tied off rows. (It's easier than weaving the ends in.) Make 2-3 more rounds and tie off.

What To Do With The Leftover Yarn
+ Use it for other projects
+ Make squares for Warm Up America
+ Save it for Lent and make a donor afghan as your Lenten discipline.