I did not know this was the latest craze!
Having bought my first "adult" colouring book recently, I was amazed at how many there are on the market and in the shops! My elderly mum has male friends who love it and who spend their days, not gently pottering about in their garden or tool shed, but colouring away... I must admit that there is something oddly addictive to starting the first page... even when you go in for a "bit" of colouring, you always want to do just that one more leaf, or that other little bit there and before you know it it's 2 hours later and you have nearly finished the page. Here are some of the bits I have been colouring from one of the more popular books. There is a reason for them to be popular: they have nice crisp drawings which do not include huge dark lines dominating the page, they can easily be cut into smaller sections and used as a greeting card to your friends.
Give it a go, it is amazingly calming :)