The Bad Decision Blocker is an iPhone app that gives you the option of blocking any of your cellphone contacts for specific periods of time (via SwissMiss). The premise is, as you might imagine, that it keeps you from making ill-advised phone calls when, um, your judgment is not what it should be. So, before you head out for a night on the town, you can make it impossible to call your ex, say, or your Mum, until the next morning.
Gmail has a similar function for email, called Mail Goggles. Basically, it requires you to solve math problems within a specific time frame, before you can send that email! They're a bit more coy about what it's for, but I think the fact that the default activation setting is late at night on weekends, pretty much explains why you might want to use it.
OK, confession time. Ever sent a drunken email or made a tipsy phone call you've regretted later? Perhaps you've been on the receiving end of one (please, no names of the person who sent it to you). Tell us your story! If we use your story on the air, we'll send you a Spark bag. Thanks!