With Posthumous Apologies to Douglas Adams
Google Images almost failed me yesterday.
Today it had no clue what to show me. Thus the Hitchhiker's Guide to the Galaxy reference.
To celebrate Pan Galactic Bubble Gum Day, you don't need to find Pan Galactic Bubble Gum. I'm almost certain it doesn't exist in our galaxy. If you can find some elsewhere, let us know.
Celebrating this special day on February 20 is actually very similar to the normal Bubble Gum Day, which this day was almost mistakenly named. All you need is some bubble gum (your choice of brand) which you then proceed to chew - and later blow bubbles with - in a nearby galaxy.
"Pan galactic" means "all the galaxies", so there are very likely sentient beings celebrating it today in many places you've never been. (There may be non-sentient critters joining the party in some sectors too.)
I realize that right about here you're thinking, "He's just making this up."
Maybe.
It's your call as to whether you believe this and join in with some bubble gum or risk being a pan galactic party pooper and suffer the consequences.