So I grabbed a handful and went back to my desk. I was craving salt and the first chip hit the spot so I ate another. And a few more. But then I became aware of another flavor. Something was off with these chips. They tasted soothing akin to stale but different.
Then the red and green colors of the chips brought on an awful suspicion.
Walking back to the break room, the coloring and design of the bag elevated the suspicion to realization.

The date code confirmed the alarming and mildly disgusting truth: 12/28/11
They were beyond stale and left an icky aftertaste that only got worse.
OK, first, I'm an idiot for not immediately recognizing the red and green chips for their obvious associated holiday.
Second, who puts out a bag of Christmas chips in June? Could this person really be guileless? This person really didn't notice the chips expired last year, or knew they were expired but thought people might enjoy them anyway? I began to suspect that someone was performing an experiment to see if engineers would eat any food left out. (The answer is, yes.)
Today a coworker went for the bag and I called his attention to the coloring. He asked, really? I nodded and told him to check the date code. He thanked me for the warning and threw them in the trash.
Having been the lab rat, I'm on the lookout for this evil scientist.