Verb - The act of recklessly (under the influence of something illicit or mind altering) going around and stealing lawn gnomes for the sake of a collection purpose. IT is definately fun to take one of your favourite gnomes with you on vacation and take pictures of that gnome from different locations in the world and send it by postcard to the original owner.
<Dude> Yo man lets get retarded and go out on the town
<Pal> Yea man i have a great idea. Let's go gnoming and jack a garbage bag full of yard ornaments.
The act of driving or walking around town and posing on either people you know, or random people's lawn. When they open the door and see everyone just standing there, their reactions are priceless.
The girls at the sleep over were bored, so they decided to go gnoming at random people's houses and laugh at their reactions.
Cruising around town while stealing yard ornaments and putting them in different places. Start at onehouse and take an ornament, then leave it at the second house a few blocks away. Continue until you get bored or someone gets hurt. Always remember to take something from the last house to return to the first house, it's only common courtesy to make sure everyone ends up with something. Also, massively important to not get caught or arrested.
You: "Duuude we had so much fun last night gnoming until we almost got caught!"
Friend: "Yes, illegally removing yard ornaments in the middle of the night sounds so much fun."