Do you want a first-class vacation complete with swimming, tennis, wholesome meals (all you can eat) and stimulating activities - on the cheap?

Go back to college.

Many colleges and universities in this country are turning into summer resorts. They're offering "vacation" programs at prices that can't be touched by the better known resort and tourists attractions.

Some quick samples:

University of California at Berkeley - One week "Berkeley Experience" from July 30 through Aug. 6 includes morning seminars on such thins as "New Sources of Energy" conducted by Nobel Prize-winner Glenn Seaborg (former head of the Atomic Energy Commision), wine-making, wine-tasting and "earthquakes" (working with Cals famous seismographic equipment and experts).

With all this stimulating knowledge, you get your meals (all you can eat), rooms and linens, swimming, tennis and tours of the San Francisco Bay area. Adults pay $150 (double occupancy) for the whole week and children pay $100 (there's a special camp for them). This comes to around $21 a day for all your meals, all activities and all recreation. What resort can match it?

University of Michigan, Ann Arbor - Family University Week is another bargain. For $140 (adults) and $50 (children) you get full room and board for one week, morning seminars with top professors, golf, tennis, swimming, concerts and even a night at "Bimbo's," the student beer hangout.

The American University, Washingtom, D.C. -From July 31 through Aug. 7, you can go to "Vacation College." Morning seminars include: performing arts (concerts and theater at Wolf Trap Farm Park or the Kennedy Center), power in government (with sessions at CIA headquarters in Langley, Va., various government departments and offices and major news bureaus) and Federal architecture (Washington's buildings and monuments.)

You get swimming, tennis and a wine and cheese party but no meals for $150 per person (room and linen included). The price includes three extra days "sightseeing" after the week's courses and activities.

Brown University, Providence, R.I. - The summer college resort program with the theme "Explorations in Time and Space" is so popular you can only get on the waiting list. Such nationally-known figures as Isaac Aslmov (scientist and science fiction writer) are affiliated with the program. Better luck next summer. The price for a week, including room, maid service, all food and swimming, is $195 per person.

Washington College, Chestertown, Md. - you get no seminars or other organized activities but you do get a nice clean room, fresh linens with a shared bath for only $450 a day (double occupancy). Chestertown is the heart of the Maryland shore area where you get fishing and crabbing on the Chesapeake Bay with Atlantic Ocean swimming nearby.

Meals cost $1.50, $20, and $3.50 for breakfast, lunch and dinner - all you can eat (inludes crabs and other local delicacies). Swimming and tennis are free. You can arrange fishing trips and sightseeing on your own.

There are two places you generally write for information on college "resort" activities: the Alumni Office or the Housing Office. The former knows about package seminar deals while the latter usually know if just plain rooms are available.

Get a map, pick the area you want to visit, them loop up colleges and universities through the education directory found in most libraries. Your librarian can help.

BOOKS AND BOOKLETS: Do you want to lose weight this summer? Or, perhaps it's the other way around - you want to gain weight to make that bathing suit look better. Either way, you can come up with a good plan by reading "Food - And Your Weight," a booklet written by diet experts Louise Page and Nancy Raper for the U.S. Department of Agriculture. You can get a copy by sending 50 cents to: Consumer Information Center, Pueblo, Colo. 81009.