You know that saying about the whole being greater than the sum of its parts? I've got three words that are plenty appealing on their own: Fridays, Fun, and Free. One marks the beginning of the weekend and the temporary end of the indentured servitude we laughingly refer to as "work." One denotes frivolity, enjoyment, and pleasure. And one sends our miserly hearts aflutter with promises of getting something for nothing. Put them all together, however, and you've got an alliterated trifecta that, if not approached with reserve and calm, could send our miserly hearts into cardiac arrhythmia. Ladies and gentlemen, I give you the 2014 version of Free Fun Fridays.

Presented by the Highland Street Foundation and continuing (on Fridays, naturally) through August 29, FFF is pretty much self-explanatory: A bunch of museums and cultural venues are opening their doors and inviting visitors in for free (on Fridays, naturally). Each week, a different group of organizations is participating.

This Friday, July 18, you could explore the Museum of Fine Arts in Boston or the Larz Anderson Auto Museum in Brookline. Heading down to the Cape? Check out the Sandwich Glass Museum. But don't bring your checkbook. Because admission is free.

On future Fridays, you could visit the USS Constitution Museum in Charlestown, the American Textile History Museum in Lowell, and the Isabella Stewart Gardner Museum in Boston, among dozens of other wonderful venues. All for nada.

Generally, the deal is: Show up on the designated Friday, don't reach for your wallet, and walk right in. But there are a few places that have special instructions. To get all of the details and a complete schedule, go to the Free Fun Fridays site. But remember to remain calm as you peruse the site, lest your miserly heart go into overdrive from all the excitement.

Photo: USS Constitution Museum