I've never done geocaching, but I have done two Urban Quests, which are essentially scavenger hunts and puzzles in various cities.
You buy the quest, which gives you a starting location and a list of questions. You need to find specific things, which contain information that answers questions that lead you to the next clue. For example, one I did involves (as one of the questions) a quest through a park that had a bunch of war memorial statues, each containing a number. You plugged the numbers asked for into an equation, and then you go to the street corner that has one of those maps of the local downtown that has numbers on it, and you go to the site whose number corresponds with the answer of the math question. That brings you to some more statues, etc. etc. etc.
Another quest brought me to a Walk of Fame, where you had to put celebrities' names into a crossword puzzle, and the final answer of the game was spelled out from those names.
In the end, you enter a Final Answer into a website (using your smartphone) and it says "you win!" and it tells you that it made a reservation for you at a restaurant close by (you pick the style of food and the price range, but the restaurant is a surprise). You buy your own food, but it's still a fun chance to try a new place out.
-Sparks Nevada, Marshal on Mars
"Who cares what evil lurks in the hearts of men!"
"Unless evil's carrying the Martini tray, darling."
-Frank and Sadie Doyle