Found this today on sale cheap and just had to buy a copy (although I prefer the phrase “invest in” rather than “buy”.
Very clever hardware has been shoehorned into five little battery powered boxes. Each shows a particular letter and when you put them in a row that makes a valid word you hear a beep and the game gives you some points. There must be a bunch of little radio serial ports and some RFID devices inside that let the blocks work out where they are, along with quite a reasonable sized dictionary.
Of course number one wife cares little about how it works, but she does enjoy playing the game, as do I. Well worth the investment. Comes with a nice little box you can carry the letters round in, along with some rather good party play modes.
One slight issue that we have noticed though is that the game seems to be fitted with an american dictionary. Which means that it is happy to accept words like "favor" and the like. This is a tad annoying, in that we bought what we thought was an english product (in all senses of the word).
Still fun though.