Full House was a hard difficulty stamp in Club Penguin. In order to obtain this stamp, you need to fill your igloo with 99 furniture items, which is the maximum amount, and then click the save button.
This stamp was released on July 26th, 2010, as one of the original stamps.
Trivia[]
An easy way is to buy a cheap furniture, costing only 10-100 coins, then buy 99 of these items, and then place them in your igloo.
In December 2015, it became a non-member stamp, due to non-members being able to buy furniture in the December 2015 edition of the Furniture & Igloo Catalog.