We have a lot of Snow Birds (people who live here in the winter and go back to their frozen wastelands in the summer) in this area. Last year one of them started a challenge cache series, and to date the series has 41 caches. Some of them aren't so bad, requiring you to spell your geocaching name with the first letter from the title of caches you have found, etc. Most, however, can only be logged by someone who has found 10,000 or more caches, which is fine for retired people who live full time in RVs and do nothing but geocache all the time (such as the guy who started the series), but that eliminates most of us who live and cache in this area year round. A few examples from this series: 1000 caches in each of five states; black out the stats grids on your profile; 100+ Earth caches; 3 caches a day for 366 days. I can go out and find all of them at any time, but I can only log a handful of them at this point.