All evenings of classical music end eventually – even most performances of Meistersinger. But after the final notes have died away, why not ask this question before you grab your coat and head for the exit? 
How did that piece of music end?
Unless you were attending a performance of a piece of atonal or 12-tone music that just stopped cold, chances are that the piece you just heard ended with a cadence, which is a harmonic wrap-up to the music. The question is, what kind of cadence did you just hear?
Cadences I Have Known and Loved
Here’s a field guide to common cadences that you might want to know about, plus some video clips that illustrate them.

A perfect cadence (also called an authentic cadence). This is the granddaddy of all cadences. In it, the composer wields the strongest harmonic tool at his or her disposal: A powerful move from the dominant chord (V) in the key to the tonic (I). You’ll find perfect cadences in both major and minor keys. In some cases, composers will make these cadences even spicier by adding a seventh to the dominant chord (V7) before it resolves to the tonic (I).
Because this V-I cadence pretty much encapsulates the entire harmonic structure of western music, you can find examples in baroque, classical, pop, American Song Book standards, you name it. However, here’s one very visible example. It comes at 7:58 the end of “Quando rapito in estasi,” the cabaletta that follows the aria “Regnava nel silencio” from Donizetti’s Lucia di Lammermoor. In this performance, you can’t miss the dominant, because Anna Netrebko belts it out beautifully for you, then resolves down to the tonic. It’s about the best-looking perfect cadence you ever saw, right?

A plagal cadence.  This one will be familiar to you – it’s found at the end of most of the hymns that are sung in church.  It’s actually a weak harmonic/acoustic resolution (for reasons that I’ll explain in a future post) that moves from the subdominant chord (IV) to the tonic (I). It can be used in both major and minor keys, but feels most natural in major.
You can hear a plagal cadence clearly at 4:45 at the end of this full-bore performance of the hymn “Love Divine, All Loves Excelling” by the Mormon Tabernacle Choir.  

A cadence that ends on a Picardy Third (called a Tierce de Picardie in French).  A piece is rolling along in a minor key. But when the final V-I perfect cadence happens, the composer lands on a major version of the tonic chord, not a minor version. (He or she does this by raising the third of the tonic chord by a half step to create a major, not minor, chord.) I used to dislike these cadences when I was a kid; after a composer had set up a nice gloomy atmosphere in a minor key, the resolution onto a cheerful major chord seemed like a cop-out.  Now, these cadences are okay with me. For some reason, the opposite kind of cadence (one that starts in a major key and ends in the minor version of the tonic chord) never seemed to catch on. (Maybe if it had, it would be called a Fifth of Bacardi® cadence?)
Here’s a great example of a Picardy Third. It’s the final cadence of the magnificent double chorus that opens Bach’s Saint Matthew Passion. In this terrific performance, the cadence takes place between 8:20 and 8:30. But of course, you’ll want to listen to the complete chorus.

A deceptive cadence. You won’t find these at the end of pieces, actually, but usually somewhere in the middle. In most cases, it will sound like a piece of music is galloping toward its final conclusion, which will be a glorious V-I perfect cadence from the dominant to the tonic. But just when you think it’s all over (and your children start to hope that the piece is finally about to end), the composer pulls a fast one and resolves the dominant (V) somewhere else – in most cases, onto the submediant (VI) chord. Then the piece has to run a while longer until the composer finally resolves onto the tonic (I) and your kids get to go home.
In this performance of Bach’s Toccata and Fugue in d minor, you can hear a big whopping deceptive cadence at exactly 8:24.

A 6/4 cadence (sometimes called a half cadence). This cadence is customarily used in the first movements of concertos, just before the solo instrument gets to play its cadenza. It’s essentially a perfect (V-I) cadence, but the tonic (I) chord is voiced in its second inversion (also called a 6/4 inversion, which is a mite too complicated for me to explain within the context of this post). It creates a kind of open-ended feeling that invites the soloist to jump in and play the cadenza.
It happens unmistakably at 12:16 into this performance of Beethoven’s Piano Concerto No. 5 (“Emperor”). Arturo Benedetti Michelangeli is rather magnificent in this historical performance, right?

Are there Other Kinds of Cadences Too?
You bet! There are many of them, some rooted in older modes of music like Dorian, Phrygian, Mixolydian, Hypomixolydian, and even more. And then we come to cadences that embody suspensions, which is a whole other topic. But the five cadences I describe above are the ones you’re most likely to hear in the concert hall.
When you hear one, you can turn to your date for the evening and say something like, “Geez, did you hear the Tierce de Picardie that ended the Kyrie?” Your erudition might, or might not, be well received. Duck fast to avoid any glancing blows, and please let me know how it went.