Perkins's tent

Perkins (Of the Misuse of Muggle Artifacts Office, and collegue of Arthur Weasley) lent the weasley family his tent to use for the Quidditch World Cup. The tent was magically charmed to be bigger on the inside than it appeared on the outside. Most likely using an Undetectable Extension Charm. It had enough room for a small kitchen, and several small bunks. Perkins allowed the Weasleys to keep the tent after his lumbago got worse and no longer had interest in camping. When Harry, Hermione, and Ron left to hunt for the Horcruxes Arthur let them take the tent with them to use. The trio used this tent for several months after leaving 12 Grimmauld Place until it was lost when the Snatchers cought them after breaking the Taboo on Voldemort's name. Shortly after, Bill Weasley lent them a similar tent to use, which they only used once before returning to Hogwarts the same day as the Battle of Hogwarts.

Behind the Scenes

 * During the Quidditch World Cup, Arthur insisted on erecting the tent without the use of magic, to avoid Muggles accidently seeing magic. It took Harry, and Hermione some time to get it ready, but managed to figure out the stakes eventually and set it up.
 * We see, in Harry Potter and the Deathly Hallows, Hermione uses Erecto to magically set up the tent.