My wife and I just happened to be at the Grimace game back in June, stopping by for a Mets game as we were driving through on the way back from a Long island weekend. I guess Grimace had thrown out the first pitch, which we missed, but it was a Mets blowout from the word go, so everyone was in a party mood right away. They kept showing Grimace in different parts of the ballpark during inning breaks and people were going nuts, and of course, this was the beginning of a long winning streak for them, which sealed the deal.
It's a toss-up as to what's the more popular meme in Queens: Grimace, or OMG.