Before the Crimson and Bulldogs battle it out on the football field tomorrow, the Harvard and Yale Glee clubs will be suiting up in their tuxedoes and fighting for the better tone quality and blend. Those choir boys can get vicious. Be there to see if a fight breaks out over the harmony at The Harvard-Yale Football Concert. 8 p.m., Sanders Theatre, 496-2222. Tickets $8/$6 for students, $14/$10 general.

I'm getting veklempt. I'll give you a topic. Sweet Honey in the Rock is neither a food product nor a rock band. Discuss. Actually, its an all-female African American quintet that performs music with black church roots, like spirituals, hymns, gospel, jazz and blues. Check out their 25th Anniversary Concert Tour tonight. 8 p.m., Symphony Hall, 301 Mass. Ave., Boston, 266-1200. Tickets $18.50 to $27.50.

Folk legend Arlo Guthrie appears at the Somerville Theatre in Davis Square tonight for some acoustic guitar and good tunes. It's someone who you can brag about seeing live in 20 years. People will think it's cool. Really. 8 p.m., 55 Davis Square, Somerville, 625-5700. Ticket prices vary.

Bibliophiles will find sanctuary at the 22nd Annual Boston International Antiquarian Book Fair. Rare books, pop culture accouterments, maps and photographs will be up for sale. Price range: $1 to $85,000.

SATURDAY 21 NOVEMBER

Those barren dorm room walls may have been acceptable in September, but now that midterms are over, they’re as tacky as keeping your Christmas lights out until Labor Day. Get in on the interior decorating action as 343 posters are auctioned at Skinners Auction Gallery. The selection ranges from The Seven Year Itch to The Day of the Triffids to Dirty Harry. And for you seniors courting first-years, try hanging Lolita or The Graduate over your bed for that suggestive effect. 3 p.m. 63 Park Plaza, Boston, 350-5400. FREE.

First-years heard the horror stories about the dread of the "bum, bum, budum, bum" of a cappella groups, but never fully understood the true terror until the jams kept coming with no end in sight. Weekend after weekend after weekend after weekend a different group vied for their money and struck fear into their hearts. But the end has come. The Harvard-Yale Jam, features The Radcliffe Pitches, The Harvard Din and Tonics, Dukes Men of Yale and Yale Whim N Rhythm. Prove that you're hardcore and make it to the encore. 8 p.m., Sanders Theatre, 496-2222. Tickets $7 for students and seniors, $10 general.

If you are not strong enough of a person to handle yet another weekend of Harvard a cappella, head over to MIT to experience MIT a cappella. The Chorallaries, a coed a cappella group, is having their Fall Concert. For once you'll see something there other than the frats. 7:30 p.m., MIT Room 10-250, 77 Mass. Ave., Cambridge, 617-225-6545. FREE.

Stop dreaming about what Adams House was like back in the day and join the celebration of multimedia at mobius 10th annualArtRages decaDance, a benefit party withperformance, video, sound, participatory and otherart forms. Live music will be provided by NeonGrandma. The only wallflowers at this bash will bepart of the installations because that artsy setcan really boogie down. 8 p.m. to midnight, 11Stillings St., 2nd floor, Boston, 542-7416.Tickets $12, $10 for students in advance, $15, $12for students as the door.

Slick your hair back and get one more use outof that zoot suit and pair of saddle shoes. Beforeswing falls out of favor and the next dance crazebecomes all the rage, catch the Brian SetzerOrchestra jump, jive and wail away. Whenformer Stray Cat Setzer jams with his 17-pieceband, the joint will be jumping. Make Vince Vaughnproud. 9 p.m., The Palladium, 261 Main St.,Worchester, 423-NEXT. Tickets $22.50.

If the Garment District is your shopping venueof choice, this Bostonian retro fashionshow is making styles from the '50s and '70snouvelle and hip again. Proceeds go toward AIDScauses. 4 to 6 p.m., 1721 Washington St./ SouthEnd, Boston. $5 in advance, $7 at door.

The Boston Pet Expo is calling allanimal-lovers. (No, that doesn't mean bestialperverts.) A smorgasbord of dogs, fish, reptiles,ponies and predatory birds are up for sale, aswell as treats and toys for pets at home. 11a.m. to 7 p.m., also Sunday, Nov. 22 at 11 a.m.-6p.m., Bayside Expo Center. Tickets $6.

Like Stella, you too can get your groove backwith a taste of warm weather cuisine. Currychicken, jerk chicken, plantains, rice, peas, andchanna will be served at the H-R Caribbean ClubFood Festival. 4:30 p.m., Ticknor Lounge.$5/plate.

Watch Mather House transform into a house offashion as haute couture-strikes withMOODS, a fashion and talent show sponsoredby the H-R Carribean Club and the BSA. 8:30p.m., Mather House Dining Hall. FREE.

If the decor of your room bespeaks HollywoodGlam, Skinner's Movie Poster Auction isnecessary hot spot to frequent this weekend.Cinemaphiles may take home original movie postersfrom Sunset Boulevard, Breakfast at Tiffany's,Psycho, and more. Invest in vintage posters,domestic and foreign, before they're going, going,gone. 3 p.m., Skinner's Auction Gallery,Heritage-on-the-Garden, 63 Park Plaza. FREE.