- A Guinea pig hotel is a piggy built structure created by right-clicking a lvl 20 guinea pig with a diamond, then standing well back. a video of a guinea pig hotel can be found here.
Guinea pig hotels do not seem to attract Guinea pigs in any way, but are useful if the player is stranded outside at night with a level 20 guinea pig and a diamond, to make a quick shelter to cower in. Other than that they are just decoration to the wacky landscape that is more creeps and weirdos(or mo' creeps and weirdos.)
Also, the hotel is stuffed with goodies, like golden apples, red apples and wheat, and can be used as a luxury kennel for guinea pigs. as such this can be ridiculously helpful, because you can simply steal all the goodies and go tame an army of guinea pigs. as long as a trickle of diamonds keeps coming in to the player they will be able to tame mass amounts of guineas.