"I don't know. What do you want to do?" Soon, you'll never say it again, thanks to entrepreneur (and my MIT friend) Brad Rosen.

Zync, is a new social networking site for something we really care about -- what to do tonight. Zync uses algorithms we'll never see to figure out what people like us like. So, if I like Salt for a dressy restaurant, Beantown Pub for a salad or burger, and Kashmir for Indian food, it will tell me the Chinese restaurant liked by people who like those too. It's like having an army of food tasters with your same preferences scout the city for you.

Ever killed an absurd amount of time calling, emailing, or texting to find a restaurant that four of you can agree on? Zync can solve that problem, too. If you and your friends sign up, it will make recommendations that should make everyone happy.

Looking for something to do on the weekend? after dinner? with the kids? Zync tracks thousands of activities, sporting events, concerts, art shows, bands, etc. Once it gets to know you, it should be able to tell you when your favorite craft fair is on, so you never miss it again.

Right now, you can sign up for a sneak preview of Zync in Boston.