[Beware: This runs long When drawing words from the honeyed recesses of a cherished memory, it's not hard to do so.]
Here it goes:
I made a point, at the start of each class, to inform the students "the first moment of spring" was imminent, and of the time-of-day that the crossover would occur. I talked, drew pictures, and wrote on the board to explain. They may already have known this stuff in general, but they really wouldn't have known it in English, I figured. I explained the Latin origin of the word 'equinox' (equal+night). I (half-)feigned personal excitement about this movement of the Sun, trying to create a "buzz" in the class about a single moment in time (i.e., the Sun crossing the equator) that would have hitherto had zero relevance to any of them.
I kept up the pace with softball questions to get students "in on it". "How excited are you that spring will start in 48 minutes? Very excited, a little excited, or not excited at all?" I went around the room, having each student choose one of those excitement-levels (easy answers). Occasionally I'd ask for elaboration. (Of course they should've been happy for spring. Twenty-thirteen's winter was long. The cold lasted even through April for some reason [see post-34].)
As I say, I half-teasingly encouraged the students to celebrate this event. I even created a "countdown" on the board, which I periodically updated as the class went on.
I was with a class of mid-level ninth-graders when the "equinox moment" hit. As soon as the bell rang to mark the start of class at 8:30 PM, I wrote "32 Minutes Till Spring" in large letters on the board. This was the countdown. I went into my little explanation, soliciting information from them (some vaguely knew the mechanics of the Sun's movements, but none could manage it in English). We went into the discussion about what this statement that "spring begins in 32 minutes" meant. I modified the number of minutes on the "countdown" as 9:02 PM approached.
I used a handheld stopwatch/clock in classes for various purposes, and when it was 9:01:30 or so, we stopped everything and did a proper countdown with that clock. It was a true New-Year's-Eve-style countdown for the last ten seconds. I was, I'm pretty sure, the only one actually saying the numbers aloud ("10...9...8..."), but that was okay with me. A few students' giggles accompanied. When the time hit 9:02, I said "Welcome to spring!" and wrote that same in enormous letters on the board. I asked the students some more questions, similar to the above. A couple of students were rolling their eyes and so on at all this, but the class was more engaged than it otherwise would've been, and that's certain. They were listening.
Students who were following all this highbrow clowning-around were actively using their English skill to understand what the heck I was talking about, and taking in new words like "equator" (for which they learned my second-syllable-stressed pronunciation, eQUAtor, not the first-syllable-stressed version of the U.S. South), all while simultaneously being "entertained" (in a manner of speaking). This beats their usual M.O. of two parts spacing-out, one part rote-memorizing. (Come to think of it, as I recall, that particular class was probably a "three parts spacing out" group.)
I have not even the foggiest recollection, nine months later, of what the "book work" we did on that day was (and they did, most of them, do some; I wouldn't waste a whole period on a diversion like this). I do remember this "equinox discussion" vividly, though, something which was of no relevance at all to any English test of theirs.
I don't know how much any of the teenagers in that room remember of me, of what I tried to teach them in my time there, but I'm willing to bet that at least a few of them remember this "equinox discussion" and got something from it.
So to repeat: I'd sometimes introduce unexpected or irrelevant topics, like talking about solstices and equinoxes, despite these things being nowhere in the textbook. I'd try to be at-once serious and lighthearted, explaining and discussing and so on for a few minutes, usually (but not always) before we started the day's real work. Some days I'd try to connect this "warm up activity" with the real work if possible. The topics I chose are ones that amused me. Amusing oneself may be the best way to amuse students. Amusing students is the key to it all.