Taken from here.
1. Go on a search for as many good climbing trees as possible, climb as high as both can in all of them, compile photo evidence.
2. Go to a major chain bookstore, and leave notes to future readers in copies of your favourite books.
3. Have her dress up as a ghost and you dress up as Pacman. Walk around downtown holding hands, and whenever anyone sees you two, pretend to be embarrassed, and run off screaming “Wocka wocka wocka.”
4. Create photo evidence suggseting that you went on an advanture that didn’t really happen.
5. Dress up as superheroes and stop at least one petty crime “ie. jaywalking, littering…”
6. Build forts out of furniture and blankets, and wage war with paper airplanes.
7. Try and visit as many people as you can in one night , and turn and many things inside their apartment upside down as you can, without them noticing.
8. Go to the airport, get the cheapest, soonest departing flight to anywhere when you show up and stay there for a weekend.
9. Write a piece of fiction together. Outside at a cafe. Ask strangers when you get stuck.
10. Dress to the nines, pretend to be married, and test drive very expensive vehicles at an auto dealership.
11. Do the lamest tourist thing in your area that you have both secretly wanted to do forever. Have an unabashed good time!
12. In the middle of the night, drive to the beach, so you arrive just as the sun is rising. Have a breakfast picnic, then fall asleep together. Bring a sun umbrella.
13. Drive somewhere unknown and have dinner in a city you’ve never been to (call each other by fake names)
14. Go to a minor league baseball game under the stars. Tell each other stories about how bad you are at athletics. Randomly cheer for both teams. Eat lots of Cracker Jacks.
15. Go around the city with sidewalk chalk and draw hearts with equations inside on random things.
16. Walk around a city and perform short silent plays in front of security cameras.
17. With a camera and a pair of boots, make a photolog of a day in the life of an invisible person.
18. Walk around the city all night and find a place to eat breakfast at dawn.
19. Go to a restaurant and convince the cook to create something completely new for you.
20. Rent a movie neither of you have seen before. Set it on mute and improvise dialogue.