Meme stocks and altcoins might seem like the biggest trends of the year, but they’re not quite. SPACs (special purpose acquisition companies) have quietly been driving investor madness since January. And, unlike interest in altcoins and meme stocks, there are no signs of this train slowing down. Coinbase (NASDAQ:COIN), Churchill Capital (NYSE:CCIV), Pershing Square Tontine Holdings (NYSE:PSTH)…