The word "at," a common preposition, is now a verb? And it can have a tense?
Obviously the English language is always changing, and I'm no stranger to words transitioning to other parts of speech. (I once wrote a whole research paper in an Advanced Grammar course on the versatility of the verb "to get" in becoming a noun in recent decades--yeah, English people are supercool.) Of course, perhaps the most famous example in the last ten years was when "Facebook," a clear proper noun, took no time at all to become a verb--"Facebook me!"
This use of "at" may be old news for today's tweeters, but I feel like I really learned something this morning. Are there any other changes in parts of speech that are becoming prevalent in our linguistic usage? Let me know!