Imagine it’s Friday afternoon and it’s up to you to plan the night. What do you do? Research on Yelp? Scan upcoming Facebook events? Grab a New York Mag or fire up Flavorpill?

What if there was a sweet service to suggest social itineraries for you in the same way Wanderfly suggests travel plans? There is! And it’s aptly called Weotta, a San Francisco based startup that launched this week at Tech Crunch Disrupt in New York City. Weotta is a brand new, social web app that answers the suggestion, “Weotta do this…” At its core, it’s a social planning product, a “occasion search engine,” if you will.

(Tech Crunch’s Arrington thinks Weotta is such a good idea that he told Google’s Marissa Mayer to check it out because, “It’s probably an idea you’d want to copy.”)

It’s so easy to use it’s taking the planning out of plans. Sign in with Facebook. Pick a theme: Business, Dating, Family, Friends or Solo. Pick a vibe: Casual, Chill, Classy, Hip, Local Style, Touristy. Then click Generate Plans. Weotta taps into hundreds of signals, scouring the web, pulling from sources such as NY Mag and Time Out New York with Facebook events on the way. Weotta is also likely to tap the following APIs: Hunch, Foursquare, Plancast and Dinevore.

Screen shot 2011 05 25 at 2.09.26 PM 520x351 Weotta launches a social planning search engine [Beta invites!]

Weotta delivers a slew of interesting itineraries based on the most current and relevant information to you and your friends using data from your Facebook. (So if you’re married and have two kids, your results will definitely be different from mine.) In true machine learning form, the app improves as you use it and as the more people around you use it. Then, simply choose a plan such as “Friendly Fires, drinks and dinner,” and easily book reservations, buy tickets or share plans on Facebook.

The web app currently works in New York City and San Francisco only, with other cities coming soon. The bootstrapped team will monetize by somehow using data pulled from its growing social graph and from affiliate links.

We caught up with CEO and Co-Founder, Grant Wernick on Weotta, which he describes as “Pandora for your social life.” [Watch the video below.] Also, since Wernick and his team are awesome, they are hooking you guys up with beta invites! Sign up here, connect with Facebook and start enjoying life planning-free.