In college, one of my classmates (who is now the conductor of an orchestra, so I guess that whole music thing worked out for him) coined the term halftime to refer to a resounding cadence in the first half of a piece, the type of cadence that might fool an inattentive or unseasoned listener into thinking that the piece is over, when in fact it's just getting started. We're not talking about a false ending, which is comparatively easy to find, but rather a "big finish" when we're nowhere near the finish.
Also sprach Zarathustra has a big halftime cadence, complete with a reprise of the opening fanfare, at the end of Der Genesende. This was the piece that inspired the coinage of the term.
Schubert's Trout Quintet has a halftime cadence in the precise center of the final movement. Warning listeners about it doesn't help.
The first movement of Mahler's Second Symphony has a massive halftime cadence. (Super sideburns version.) The piece closed Gerard Schwarz's final concert (for nitpickers: Schwarz's final regular-season concert as music director of the Seattle Symphony), and when the halftime cadence was reached, I heard scattered applause through the hall. Which told me a few things.
- The people who attended that concert were not regular concert-goers. Another cue was that people were far more nattily-dressed than your average Seattle Symphony crowd, and we were in the third tier! (Now, I don't normally sit in the third tier, so who knows, maybe the third-tier crowd is the dress-up crowd.)
- The people who applauded under the mistaken impression that the piece was over were in for a big disappointment, since there was another hour to go!
Can you come up with other examples of halftime?
False ending sidebar: Haydn is famous for false endings and other tricks. Here's a fun story about selling the false ending in Haydn's 90th.