Not Driving Under the Influence... Dialing Under the Influence (more commonly known as Drunken Dialing). That's the goal of this service from Virgin Mobile Australia:

Incoherent calls to exes, bosses and partners could be a thing of the past as Virgin Mobile urges you to get tighter with the right posse.

Dial 333 plus a phone number you don’t want to call when drunk e.g. 333 0431 123456.

Virgin Mobile then stops all calls to that number (e.g. 0431 123456) by blacklisting it until 6am the following morning from your phone.

I suppose drunken calls to bosses might not be good... but I think that drunken dialing exes is rather important. How else is a woman supposed to know how much she really meant to the guy who's heart she just stomped on, if she doesn't at some point get that incoherent call at 2 AM begging her back, or asking for just one more romp in the sack? We drunken dial with your feelings in mind ladies! Don't forget that! Not that I've ever done that of course. *cough*

It is a clever service offering though, costing only 25 cents each time you use it. No word yet on whether they offer this in other countries as well.