[Disclaimer: This doesn't have too much to do on programming or dev stuff]
Earlier today I went to the library (the physical place) and just decided to sit down with some books on computer stuff, at some point I went into the "Education" section to see if they had like how to stuff on programming or whatever, and I found a palm sized rock that was painted white on one side with a dragon hidden behind a book. It said on the back "Post on FB. Keep or rehide"...
So I got my phone out and opened FaceBook, and the first post that showed said "I just hid a bunch of rocks at the Library and [The name of a park nearby]".
I posted some pictures of the rock and mentioned the friend on mine that hid it, and went to another section to hide it again.
I found a second one that said "Be yourself" and the same "Post on FB, keep or rehide" message, one with a Monster on it and at the park there was a mouse eating a piece of cheese.
The mouse one I kept for myself. :D