The Fourth Annual Fairfax Fair, with activities ranging from a petting zoo to sporting events and the Virginia State Championship Chili Cook-Off, will be held on the campus of George Mason University this weekend.

The chili cook-off, and a statewide barbecue cook-off, will be held both days. The fair opens Saturday from noon to 8 p.m., and it continues Sunday from noon to 5 p.m. Any restaurant or individual may enter the cooking contests judged each day.

The Fabulous Hubcaps, a '50s revival musical group, will perform at 7:30 p.m. Saturday. Sunday is sports day, with special sporting events for Father's Day and appearances by members of the Washington Redskins, Capitals and Bullets. There will be a demonstration tennis match and special sporting competitions for children.

Several area stores, including Garfinckel's and J.C. Penney, as well as businesses such as AT&T and MCI communications companies, will be operating information booths, and some of the stores plan to sell merchandise. There will also be craft demonstrations, sales and competitions.

Organizations such as Mothers Against Drunk Driving (MADD), the Lupus Foundation and Alanon will participate in an informational health fair. For children of all ages there will be clowns, mimes, games, 4-H pony rides and hay rides. Country music radio station WKIX will broadcast live from the fair both days.

The fair is sponsored by the Northern Virginia Regional Park Authority. To get to George Mason University, take I-66 to Rte. 123 toward Occoquan until reaching University Drive. There is no admission charge, and the fair will be held on all parts of the campus. Call 691-FAIR for more information.