It's a very good idea (even without sponsorship, without July). If you can't go a week without a drink, what does it really say about you? Eh? I did a month last January, in part because of my non-drinkin' muslim flat-mate. He pointed out, perhaps correctly, that from his point of view drunks look stupid. If you've ever been designated driver a few times you know exactly what he means. I walk past pubs all the time and frankly the clientele look like a bunch of annoying, loud dumb arses. So, I decided to try a month of no drinking.

The first week is *hard*, the second is two. By the third you're OK. The fourth week you'll be honestly enjoying not drinking, and then a little sad even when you have your first drink again after the month is over.

Interestingly, I tried to do another month starting just a few weeks ago.
I was fine after the first week, and the second too.
Prognosis: ****ing boring, so I stopped.

Honest or what?
So, your mileage may vary. But it's worth a try just to see what it's like, because when was the last time (decade?) you went without a drink for a week?
BTW: Anyone noticed the James Squire billboards? What the hell is with those? Super boozy looking guy (homeless even) with a tag, one I saw last night was something like "tonight I sleep here, tomorrow who knows?"