This is true, I’m not making it up – there are several companies (online) that sell grass paint. Some companies (see video link) will even come out to your house and paint your lawn for you.
I’ve heard some weird and wonderful things in my time, but I can’t really get my head around this – surely if the grass is dull and yellow, it’s because it’s dying and needs watering – not painting!
The paint is meant to be non-toxic, good for the grass (err!) and a single application should last 90 days – not bad for $400!