Hubby and I have been
geocaching on and off over the past year(ish) and were visiting several Minnesota state parks over our vacation last week - we had no idea, but the state parks here are sponsoring geocaches (one in each state park) as part of a MN History Challenge. A lot of them are multi-caches, which means you find a cache and it gives you the coordinates for the next cache in the chain, and send you to areas of the park you might otherwise have missed.
I'm not sure if they'll be around past December as the descriptions all say this is a year long program, so I thought I'd put out a blurb for anyone else who might be geocaching in MN and hadn't heard about it. We've had a lot of fun with this anyhow!