While clearly not nearly as fun as "Talk Like a Pirate Day", this still struck me and kind of interesting.  Some creative ideas at the link below.

My favorite was.....

"Walk up to random people and say 'WHAT YEAR IS THIS?' and when they tell you, get quiet and then say "Then there's still time!" and run off. "

Though this one had merit too .....

"Take some trinket with you (it can be anything really), hand it to some stranger, along with a phone number and say 'In thirty years dial this number. You'll know what to do after that.' Then slip away. "

Pretend to be a Time Traveler Day | Geekdad from Wired.com