My 6 yr old son told me a cute pshat in shofar during a Rosh Hashana seuda, one that I never heard before.
The Soton knows that when Moshiach comes, the great shofar will sound, and Hashem will ??? the Soton for good. So when it is Rosh Hashana, Hashem in His everlasting rachamim, commanded us to blow the shofar, this way the Soton shudders and runs and hides (thinking that perhaps Moshiach arrived), and now when Hashem sits to judge the soton is not around to prosecute!