Comedian and writer Jeff Klinger (twitter.com/jeffklinger) joins Matt, Andy and Jesse this week to talk about: Malfunctioning Segways! Andy's HP laptop woes! Two-saucer setups! Expensive anatomical models! Figuring out when man's anscestors developed a tolerance for booze! Getting slightly racist about alcoholism! Stealing liquor from your parents! Matt touched living legend Buzz Aldrin! The abuses of management consulting! Jesse going to school in a white tuxedo! Curing acid reflux by clamping your esophagus! Mole penises! Space water corrections!

Comedy writer Michael James Nelson (michaeljamesnelson.com) has worked on Betty White's Off Their Rockers and many other shows in spite of the fact that as a young man he was convinced he would pursue a career in science and work on the Space Shuttle. He joins Matt, Andy and return guest Robert Buscemi this week to talk about: Magnet schools: How do they work? Growing up with multiple learning disabilities! The varying definitions of nerd-dom! The awesomeness of Betty White! Nice pranks! Last week's asteroid close-call! Fox News and their assessment of the value of space water! Drilling into the surface of Mars! Space cats! Using color patterns to search for extraterrestrial life! The bones of Richard III! The uncertainty principle demonstrated on a (somewhat) grand scale! Literal pecking orders! How to get alpha eggs at your local grocery store!

David Huntsberger (twitter.com/huntsbergerjunk) from Professor Blastoff (professorblastoff.com), a podcast that Probably Science in no way plagiarizes, joins Matt and Andy this week to discuss: Getting deputized to substitute teach under Texas educational martial law! Narrowly avoiding dating minors! Trash-talking Bear Grylls! Ill-fitting letter jackets! High school rodeo teams! The redundancy of assless chaps! Team roping! A monkey midwife! Are there more types of otters than bears? The importance of giant prime numbers! The loneliness of Google Street View team members! The uselessness of Yelp reviews! The unintentional upside of oceanic pollution!

Dr. Peter McGraw (twitter.com/petermcgraw) heads the Humor Research Lab (HuRL) at UC Boulder, and he joins Matt, Andy and returning guest Baron Vaughn (twitter.com/barvonblaq) for a special episode devoted entirely to the science of why things are funny. Peter's Benign Violation Theory is a robust, empirically testable explanation of humor in all its forms, and it's the basis of Peter and Joel Warner's upcoming book The Humor Code. For more information on Peter's work, visit humorcode.com and humorresearchlab.org.

Probably Science completes the Austin Stories trifecta this week with comedian/writer guest Laura House (twitter.com/imlaurahouse), who joins Matt and Andy in discussing: Valley celebrity encounters! Pissing off Jamie Foxx! Chili competitions! Drinking and guns! Shooting pesky mink! Russell Crowe's crappy Twitter feed! Getting an adult ego check from your parents! Making your own bullets! Detecing the dark matter all around us! Flu shots during pregnancy are safe! The history of vaccines! Vibrating steering wheels to help drunks! Trilogy's dot com-era recruiting practices! Light that travels faster than light!

Pride of Australia Wil Anderson (twitter.com/wilanderson) delivers in a big way this week as he joins Matt and Andy this week to get to the bottom of: US/Australia alliances! The unavoidable presence of Yahoo Serious! Ned Kelly's branding prowess! Ozploitation! Adding a new color to Australia's temperature charts! Climate change denial! Karl Kruszelnicki's study of belly button fluff! Being laughed at vs. being laughed with! Testing 18 molar sulfuric acid on your arm! Exploding ATVs! Fetuses need light, too! Mark McGrath's Ark! Being lonely lowers your immune system! Comedians: Braver than Navy Seals! Crustaceans can feel pain! Pubic lice becoming extinct! Getting crabs in your eyelashes!

Comedians Dan Telfer (twitter.com/dantelfer) and Hannah Gansen (twitter.com/hannahgansen) join Matt and Andy this week to chat about: Getting a fake baby at age 18! Brussel Sprouts! Bobak Ferdowski, the NASA mohawk guy! Making origami cranes as astronaut training! Shoulder hair! The tiger quoll! Blowing up dollhouses! Fingers and toes wrinkle underwater for better grip! Debunking ridiculous lessons from teachers! Sending secret messages via Skype! Ancient eye medicine!

As promised, Jesse Case (twitter.com/jessecase) brings the first installment of Probably History, in which he, Jack Robichaud (twitter.com/jackrobichaud), Richard Bain (twitter.com/dickbain) and Andy Wood (twitter.com/andytwood) discuss the history of Christmas. Enjoy, and be on the lookout for a new episode of Probably Science next week!

Matt and Brooks are still out of town, so Andy sat down with Jesse Case this week for a special holiday bonus episode that's light on science, but heavy on the discussion of World War II bunker dogs, Jelly Bellies, porn, hospice situations, home videos from the 1980s, Beatles fandom, sleep-eating roommates and failed attempts to reach subglacial lakes. Enjoy, and we'll be back soon with full episodes and maybe even some Probably History!

Troy Conrad (troyconrad.net) is a comedian, writer, director and producer, and he's the man behind the hilarious improvised standup comedy show Set List. He joins Matt, Andy and Jesse Case on this week's episode to talk about: Breaking Bad spoilers! Improvised debate! House/career dysmorphia! Hot tub clothing regulations! Comedy Jesus! Troy's Scientology experience! Probably History! Religions with boats! Beetles with handles! Howard Bloom! Tracking space debris! Inappropriate cell phone conversation volume! Keeping bread from growing mold! The Grand Canyon: Older than we thought?