1. Go outside, and if you see someone, take the random person and make out with him/her, and say: "Yes! I finally got my dramatic kissing scene!"

2. Lay on your stomach in a puddle and scream: "I'm drowning, I'm drowning!"

3. In the pasanger seat of the car, roll your window down, stick your tongue out, soaking the driver: "I wonder why dogs only do this when its sunny out!" and laugh.

4. Make a farting noise, and say "Hear that thunder roar!"

5. When your outside, run around (reading lyrics) and scream words to Singing in the Rain.

6. Make someone laugh. Then look at them: "Gosh, your face is all wet. Suck it up, stop crying!"

7. Sit outside, and read an old book, and keep yelling "DAMN YOU, SKIES! WHY IS IT SO FUCKING WET HERE!" when your pages get soaked.

8. Gather all the family electronics, and lay them out on the grass on the curb, and let them get all wet.

9. When the family sees say: "I told you that (baby sibling/cousin/hated younng person) was evil!

10. Sit on the corner at the sewer, and hold out an empty can of soup with a sign on it "Poor, and Wet," and hope you don't get kidnapped.

11. Tell everyone around you that rain actually signifies the zombie apocalypse and that the term "acid rain" actually means rain that turns you into a zombie. Then put your hand outside the door, or window, and walk like a zombie. (Basically, start a fun/play zombie apocalypse.)

12. Collect all the neighborhood cats/felines and place them outdoors to go insane.

13. Place an empty inflatable pool anywhere outside that you can, and watch it fill up. Then place your younger sibling/a friend's younger sibling in it and tell them to go swimming.

14. For any cooking that requires water, place the bowl with all other necessary ingredients in it, let the water fill up, and make somebody nasty baking!

15. Go to the local pool, and bang on the doors because you want them to open, because it's so hot outside and you need to cool off in the pool.

Also, let me tell you that these are in no way ethical, or moral and performing the listed actions show a lacking in propriety and maturity. There's no reason to do any of these; they're just immature tactics to LAUGH at. Not attempt.
Have a nice day!