From the Great Urban Race to Leslie’s Valentine’s Day puzzle challenge on Parks & Rec, we’ve covered scavenger hunts and puzzle-game quests on the blog several times in the past.

Scavenger hunts have a special place in my heart as a puzzler, because they’re the pinnacle of puzzly thinking on the fly. Deductive reasoning, creativity, ingenuity, a penchant for plotting and executing step-by-step moves to conquer a challenge… scavenger hunts combine all of these features (and throw in some exercise, for better or for worse).

Now, for the uninitiated, scavenger hunts at their simplest are games where individuals (or, more often, teams) are assigned a list of items to obtain or actions to perform, and the first person or team who completes the list is the winner.

Scavenger hunts by definition incorporate a spirit of silliness, lightheartedness, and frivolity. Whether you’re hunting down the gaudiest things you can find at a tag sale or photographing yourself getting a piggyback ride from a police officer, the goal of most scavenger hunts is to have fun.

And it seems like scavenger hunts are becoming more creative and more diabolical with every passing day. Let’s take a look at two of the most ambitious scavenger hunts challenging players these days.

The first is GISHWHES, a.k.a. The Greatest International Scavenger Hunt the World Has Ever Seen.

GISHWHES combines the playfulness of scavenger hunts with a humanitarian ideal, challenging players to make the world a better and more interesting place through their challenges.

Designed to be played around the world through the Internet, GISHWHES has previously tasked its players to perform such varied feats as performing puppet shows for sick kids and documenting a session of ski yoga. Creating art, doing good, and being gloriously silly is what GISHWHES is all about.

The second scavenger hunt is called Midnight Madness, and was recently profiled on Quartz.com.

A high-concept game that became a brilliantly-clever fundraiser when Goldman Sachs got involved, Midnight Madness is a fiendishly challenging series of puzzles and activities scattered throughout New York City.

Goldman Sachs employees — every division of the company is represented — race around the city, unraveling electrical puzzles, playing laser mini golf, and deciphering complex clues, all in the hopes of determining the location of the next challenge.

The most recent edition of the game lasted fifteen hours and raised over a million dollars for charity. While it’s much more exclusive than GISHWHES, Midnight Madness has the same humanitarian spirit and the same sense of ambitious lunacy at its heart.

For puzzly fun on the run, scavenger hunts can’t be beat.