I heard about letterboxing through BYU's MBASA. Apparently it's a glorified treasure hunt. You find clues online, go find boxes in your area, and add your stamp to a pad inside to prove you've been there. You also get to stamp your own pad with a stamp provided in the box.
Our family decided to try it out last weekend, and we had a great time. We got to see all kinds of new things, and we didn't have to plan it out. The clues did the searching for us. Sadly, I forgot my camera. And since I refuse to pay the money to upload the pictures I took on my phone, you get the following stellar pictures. Hope you can even see what we did... I'll add captions just in case.

Our first discovery was in the MOA parking lot at BYU. Someone was apparently moving out... and into their car. It was amazing the things they had in their car. If only you could really see what we saw!

Our first clue started us at the statue of Brigham Young in front of the ASB.

Then we got to look at the statues North of the HFAC. Ellie wanted to get in the water, but since it was a rainy day... we said that wasn't such a good idea. She did throw a penny in though! (Of course, I think she would have rather pocketed the penny).
Here is Ellie holding her first treasure box! Before this, she and Daddy held a baby butterfly (a.k.a baby caterpillar). She really enjoyed that.

Standing on a bridge in one of the parks we were sent to. Meg was a good girl and hung out in her car seat all day. Not the most fun ever, but she was a good sport.

Walking with Daddy in the park we went to.

Watching a train go by. Ellie loves trains, and this was a big highlight.
Overall, it was a great adventure we hope to keep up. A wonderful free activity for those college years. We even got a first finder's prize on our second box!