You’re hurrying along the sidewalk on the way to work, running late and not in the greatest mood, when you see a sign in the adjacent field that simply reads “PLEASE WAIT HERE, YOUR FUTURE SELF WILL MEET YOU SHORTLY.” How does that affect your day? Little moments like these can bring some much-needed levity to the world around us, especially in dark times.

Impeccably produced, often enticing you to push a button or take a card, these guerrilla installations look pretty legit until you stop to read what they say. They’re easy to miss, if you’re hustling too quickly and tuning out your surroundings – but if you take a moment to notice them, they might just make you smile.

Artist Michael Pederson (aka Miguel Marquez Outside) creates these little interventions and puts them up all over his home city. Sometimes they’re site-specific, referring to things that can be found in the local environment, like a hole in the curb or a sidewalk that ends abruptly.

The personal space cards would actually be pretty handy, and who wouldn’t be tempted by a time travel pay phone? Check out more of Pederson’s work at his tumblr and Instagram.