A carpet?! Yes, that's what my (most likely horrified) husband will surely ask when I propose the idea tonight. Laure's post on painted patterned floors got me thinking. We have an addition with a very old and rather dingy berber carpet. It's on our wish list to put in wood floors to tie the room in with the rest of our home, however it's not a budget priority at the moment. So what to do in the mean time? Here are some ideas...
The original inspiration came from Domino's spread on Mary McDonald's guesthouse where she painted a large sisal rug. While the scale and bold color contrast were interesting, they were a bit over the top for my personal tastes. Still the idea of having a geometric pattern enliven a dingy rug was intriguing... 
After scouring the web, I've found two fairly clear set of instructions on how to go about beautifying (destroying?) your carpet/rug. The consensus seems to be that coarser, sturdier products such as sisal, jute, seagrass and berber are more receptive to paint than your standard plush carpet, which would become impossibly hard and matted if treated with paint.
How To Instructions:
Click here for Curbly's DIY Maven's easy to follow instructions.

Click here for Real Simple's directions.
The instructions above are intended for creating a border, but I think the same principles could be applied in order to create a patterned design.
Pattern Inspiration Ideas:
Trina Turk's Trellis and Sunglass Prints for Schumacher

Ballard Designs' Trellis Wallpaper
Kelly Wearslter's Asian Trellis Latticework for Schumacher
For barefoot comfort and for aesthetic reasons, painting a limited area, like a border or a pattern, rather than the entire carpet or rug seems like the way to go. Paint obviously changes the texture, making the carpet hard and crunchy if applied too thickly. I think that if we do pull the trigger on this one, a simple tone on tone pattern will work best.

Insane? Inventive? Tacky? What's your take?
(Images: 1,3: Curbly, 2,8 : Domino, 4: Real Simple, 5,6,8: Schumacher, 7: Ballard Designs)

Sheex Bedding
I think this is a great idea for a tired rug. I wonder if you used a fabric paint it would cut down on the matted look for a plush-er rug.
or what about concentrated rit dye? i'd experiment on a carpet remnant first, but why not?
My mom painted an area rug with fabric dye when I was a kid. It was alright at first; but, quickly became troublesome. Whenever it was walked on with wet, after-bath feet, the dye would bleed.
I don't know if it was a bad idea or just user-error on the part of my mom. However, I would steer clear of using fabric dye to do the job you propose.
I love the rug in Mary McDonald's guesthouse - I could easily see something like that in my place...
Wasn't there something about upholstery paint on AT a month or so ago? Someone painted an upholstered footstool. Using it on a rug rather than regular paint might minimize the matting problem.
perfect for when you can't find that "just-right" pattern or design!
Yup. Here's the post about upholstery spray:
http://www.apartmenttherapy.com/chicago/how-to/how-to-upholstery-spray-paint-082322
Also, go here: http://simplespray.com/ If you click on the "Upholstery fabric paint" picture on the right side of the page, it will take you to a description of the product. At the VERY bottom of the page (keep scrolling) there is a letter from a woman who painted her RV's carpet using that stuff. She mentions having her grandkids traipse through with wet feet while on vacation, but the carpet color stood up and didn't bleed. So it could work!
In last month's Elle Decor, Ali Wentworth painted a design on her family's living room carpet after kids and dogs left it looking yucky. Though the result was not really my style, it's definitely worth considering as a stop-gap while you save for a new rug.
I had an old dog with a bad prostate that "went" a lot inside. It wasn't worth it to spend much money on a nice carpet that would get ruined, so I painted an old carpet with the perfect colors and pattern for my apartment (similar to the trellis wallpaper) and actually applied the paint thickly and added some varnish on top. It was not a soft carpet but it was super easy to clean and looked great.
I was just going to say, it would have to be a harder rug -- sisal, jute, etc -- but you said it after the jump. It would be a lot of work to get the pattern on one of those rugs, in order to paint it, but it could turn out great!
Laura
http://www.grafxnerd.net
Any one have ideas for easy stencils to use? I'm not an experienced DIYer and I can see this going awry very quickly.
How about mixing textile medium into your everyday acrylic paint?
http://painting.about.com/cs/fabricpainting/gr/pr_GoldenGAC900.htm
not sure about you, but the textile medium releases "formaldehyde" fumes... i'd rather skip it and use a thicker, more durable carpet.
As posted, you can't do large prints all over a carpet or it gets still and really can't be cleaned any longer. I wonder if a fabric paint would work better.....or maybe some company out there needs to come up with a carpet paint. It would be a BIG seller!
Not still................stiff. Sorry.
Dye needs to be heat set which is aproblem with insatlled carpet -- although maybe a careful application of a blow dryer would be enough -- I'd test that idea on scrap before using it on a floor, though. (Dye it, dry it, heat set it, then get it wet and see if it bleeds...)
For the berber in question, I'd go for a serious professional steam cleaning and see if that is enough.
When I was a kid (early 70s) my mother took an old piece of wall-to-wall carpet remnant and had it bound. She flipped it over, and painted (with latex wall paints) on the REVERSE side, and it survives in great condition to this day! It's definitely not soft to walk on, but it looks great, and has definitely held up very well over the years.
As a professional carpet cleaner, you may want to make sure the paint or dye you are using will not transfer from the rug to your shoes, or feet, and back onto other capreted areas of the home. Going from a blue painted rug to a nice white carpet, you want to make sure your fun art work doesn end up costing you hundreds in replacing carpet. Rug Cleaning
Awesome. I have used something called Vecco, which is specifically made to paint carpets and area rugs. You should check them out at veccostudio.com
I have a rescue dog that marked a carpet mutiple times at a new apartment. The carpe has been cleaned, but still glows nder black light. Anyone know if painting will cover that?