40401 LEGO Monthly Mini Model Build Dog and Cat Friendship Day

The Monthly Mini Model Build was a free building event at LEGO Stores. Each month the store set out the parts for a small model, children built it there with the staff, and took it home in a bag. It began at the end of 2008 with a snowman, in stores in the United States, the United Kingdom and Germany, and spread to LEGO Stores elsewhere. The early models had MMMB numbers, and from 2012 they got ordinary set numbers in the 40000 range. The models followed the calendar, with turkeys in November, pumpkins and monsters in October and snowmen or gifts in December, and the 2020 models each marked a day of the year, such as Kindness Day and Human Rights Day. From 2016 a place had to be booked ahead. The program was retired in 2020 while LEGO Stores were closed, and the instructions for every model are still on LEGO's website.

Monthly Mini Model Build consists of 153 sets that ran from 2008 to 2020. As of today, Beach Chair is the most valuable Monthly Mini Model Build set with an estimated new/factory sealed value of $95.