The Philadelphia Science Festival is back for its sixth year, starting today, with almost 100 events planned all over the city over nine days. That's a lot of sciencey fun to tackle, but to make it easier, we've combed through the calendar and picked out some of the coolest workshops, demonstrations, parties, lectures, and tours. Get ready to get nerdy.

For more information on the science fest, go to philasciencefestival.org.

Fun With Kitchen Science

If your DVR is loaded with episodes of Good Eats, you know that the art of cooking is loaded with science. This interactive event shows foodies how their taste buds work, how scientists figure out the nutritional information you see on a food package, and how to make the perfect chocolate chip cookie.

2-4 p.m., Sunday, Free Library of Philadelphia, 1901 Vine St. Free.

Science at Play for the Young at Heart

Science and technology aren't always about hard questions, groundbreaking inventions, and mathematical equations. Sometimes, they can just be fun. Unleash your inner child by playing with BattleBots, making your own version of Silly Putty, and checking out the Chemical Heritage Foundation's impressive collection of 250 science kits and toys.

6:30-9 p.m., Tuesday, Chemical Heritage Foundation, 315 Chestnut St., $10. For ages 18 and older.

Science of Fear

Ever wonder why certain things - spiders, heights, public speaking - give you the creeps? Or why we feel fear at all? This presentation will cover the whys and hows of fear, and give you the chance to confront some scary objects and situations and have your physical fear response measured.

7-9 p.m., Wednesday, Franklin Institute, 222 N. 20th St, $10.

Grow a Pint

How much do you know about the beer you drink, besides that it tastes good? Experts from the Morris Arboretum and Yards Brewing Co. talk about the plants that go into a pint and lead hands-on experiments while you enjoy the Yards' special science-fest brew, Orang'n of Species.

7:30-10:30 p.m., Thursday, Yards Brewing Co., 901 N. Delaware Ave., $15. For ages 21 and up.

Gross Anatomy: The Human Microbiome

You might not know it, but you're an ecosystem. You have trillions of bacteria and other microbes living on and inside of you, and they are vital to keeping you alive and functioning. In this unique cabaret, researchers and a theater troupe will bring some of our microscopic hangers-on to larger-than-life size and show you what they do.

6:30-8:30 p.m., Thursday, Ruba Club Studios, 416 Green St., $10. For ages 21 and up.

Medicine 1776

In 1776, a bunch of guys were in a room downtown founding a new country. What would have happened if one of them had fallen ill, or needed surgery? This tour will take you back a few hundred years to show you what medicine was like in the early days of the U.S.A. You'll see Pennsylvania Hospital's original surgical amphitheater, where surgeries were a little less sanitary and more painful than today (no anesthetics yet) and get to look through antique microscopes.

Noon to 3 p.m., Sunday, Pennsylvania Hospital, 800 Spruce St. (enter at the Archway on Eighth St.). Free.

Astronomy Night

Astronomers will bring their gear to more than 25 sites around the city for one of the biggest stargazing parties in the country. In addition to ogling the cosmos, you can try reaching them by launching Alka-Seltzer-powered rockets.

7:30-10:30 p.m., Friday Saturday, at various locations (visit philasciencefestival.org). Free.

Science Carnival

The festival's signature event moves this year from the Benjamin Franklin Parkway to the Great Plaza at Penn's Landing and features 150-plus exhibitions, hands-on experiments, and performances, including live animals from the Philadelphia Zoo, sumo-wrestling robots, and DNA extractions.

10 a.m.-4 p.m., April 30, Great Plaza at Penn's Landing, 101 S. Columbus Blvd. Free.