I think the grass scanner idea by the RCA Design Interactions show (UK) is brilliant.
The Grass Scanner, a device designed by Alice Wang that measures how green your grass is. Using 3 Pantone Color Cue devices, it takes readings from three random patches of the grass and outputs a Pantone colour code for one to compare. With the codes, one can refer to the PARKTONE cards which contain average grass colours of Royal Parks and other green areas in the UK for people to match up with their own garden... and feel like dismal failures in comparison. For example, I am sunk as it has no yellowing brown tones.
It is precise too as grass condition in different areas of a given park may vary, each area was measured several times before an average of the data was used to create the PARKTONE card.
I am not sure what it is like in other parts of the world, but in the UK, an unofficial 'How Green Is Your Lawn' competition takes place every summer. The competition pays particular attention to people's front lawns, leaving no need for an excuse to peer over the garden fence.