It was a “What Do You Do With a Drunken Sailor” sort of a show, not too memorable musically, and I don’t recall much else except for one thing: One of the musicians was playing a little wind instrument I’d never seen before, and I wanted to have one. During the break I somehow negotiated a swap: my lucky Eisenhower silver dollar for a silver-colored Generation flageolet, a.k.a. pennywhistle, with a blue plastic mouthpiece. It turned out to be a good deal. There are lots of reasons for whistles’ popularity. They usually don’t cost much, they have more style than plastic recorders, and they seem to be easy to play. For me, there’s something maddeningly irresistible about a musical instrument that appears at first glance to be very simple but turns out to be surprisingly complicated.

The musical possibilities are almost unlimited. An intrepid tin whistler can double-tongue Bach, play through his nose just like Rahsaan Roland Kirk, entice wallflowers into frenzied clogging, whip through Balkan freilachs, and, practically in the same breath, wring out an Irish lament. When placed in the right hands and between the right lips, a whistle can perfectly evoke a misty morning at Hadrian’s Wall or a windy hillside in County Galway. A whistle is also said to make a wicked good babe magnet, especially if the player can manage to maintain eye contact with the audience while playing. All this from a musical instrument that is waterproof, weatherproof and basically indestructible.

These innocent-looking instruments are called “pennywhistles” because originally they were inexpensively mass-produced. Some of the earliest commercially manufactured whistles were built out of a long cone of tin, which is why they’re also called “tin whistles,” regardless of what material they’re really made of. The tubes were punched with holes, turned and soldered on a tapering form. The instruments were finished with plugs made of lead — imagine IQ sliding with each tune played — or wood at the blowing end.

The typical whistle has just six holes, all located on top of the tube. You can play a straight “do-re-mi” scale by covering all the holes, blowing gently and lifting your fingers one by one. Putting all of your fingers back down and blowing a little harder lets you reach the final high “do.” That makes eight notes: do re mi fa sol la ti do. Producing four other pitches that complete the standard 12-note scale requires tricky fingerings, half-covered holes and other digital contortions.

Like harmonicas, whistles come in different keys. The bigger the whistle, the lower the pitch and the greater the finger stretch needed to cover those six holes. In the late 1970s, a gent named Bernard Overton in central England designed a “low D whistle,” which looks sort of like an exhaust pipe from an old VW Bug. This instrument requires a very long finger-stretch and is pitched like a modern concert flute. The low whistle was popularized by Davy Spillane, an Irish piper and whistle player and one of the original musicians in the Riverdance lineup. This is the instrument you’ve heard on so many — some say too many — soundtracks and world-music collaborations since the mid-1990s.

Not all pennywhistles these days are cheap. The good old Generation is still made in Oswestry, England. It comes in six different keys, nickel-plated with a blue plastic mouthpiece, or in natural brass with a red mouthpiece, and costs a few hundred pennies. The marvelous works of art made in solid sterling silver by Michael Copeland in Philadelphia can set you back several hundred dollars. The price doesn’t make the sound, though. A player with chops can drop your jaw with a $5 whistle just as easily as with a $500 one.

According to Grey Larsen, a whistle maven from the Midwest and author of The Essential Guide to Irish Flute and Tin Whistle, written records in Ireland dating as far back as the 3rd century A.D. mention tin whistles. Different kinds of fipple flutes — instruments that have a wind-way to direct your air, rather than a hole to blow across, like a modern flute — crop up all over Europe and North America. Recorders and slide-whistles are also fipple flutes.

A tin whistle played well in the Irish style becomes a living thing; trilling, pulsing, rolling and lilting from one end of a tune to the other. A good portion of Larsen’s Guide is dedicated to descriptions of traditional playing styles and the ornamentation thereof. In imitation of the style of the bagpipes — another instrument indigenous to traditional Irish dance-music — the whistle is played as if the mouth were separated from the source of the air. That means that little tonguing is allowed to divide one note from another. Accents and stops are accomplished mainly with the fingers, with little grace notes dropped in between notes and to ornament phrases.

My early attempts at tin-whistle playing were embarrassingly squeaky. Since I’d been playing clarinet off and on since the second grade, I started off trying to “tongue” each note — a standard clarinet technique. I quickly discovered that tonguing pops the instrument into a higher octave, which is often shrill, and not where I really wanted my music to be.

Lots of miles of late-night walking and playing outdoors — the plastic mouthpiece lets you play even in sub-zero conditions with no fear of sticking to your instrument — taught me that the soft touch is the right one. But hours of listening to some of the best Irish players on record — Sean Potts and Paddy Moloney from the Chieftains, Cathal McConnell from the Boys of the Lough, Liam O’Flynn from Planxty and Matt Molloy from the Bothy Band, for starters — convinced me that I’d never come close to achieving the “right sound” I heard from these musicians. They all sounded as if they’d been playing since birth.

It was almost 10 years later, when I stopped trying to emulate and began to develop my own style, that I finally discovered I could get a good sound, and could convince others that I was a whistle player myself.

Thirty-two years after that first lucky swap, I’ve managed to acquire about 50 books of Irish dance tunes and more than 100 whistles, from antique to ultra-modern. Just last week, at an Irish import shop in Saratoga, I bought myself another new whistle, a Susato made in North Carolina. It’s in the key of B, which I have never seen before. I may not be Sean Potts or Liam O’Flynn, but to me nothing could feel better than coming home, sitting down and playing that new whistle for hours. It’s a sweet addiction.