Even for those who have never visited England, the name Glastonbury will likely ring a bell (no pun intended), even if it's just from its passing mention in TDVC.
The now-ruined Abbey at Glastonbury is England's oldest church establishment, known as 'the cradle of Christianity in England' since the English Church began here. The town is firmly associated with the legend of Joseph Of Arimatheia bringing the Chalice or Grail here, along with some of the original disciples (perhaps including Mary), who built the first church in Britain here. (Note that the legend is considered historically unsubstantiated, and on the official Abbey site, there is nary a whisper about the' Old Church' on its History Of The Abbey page - you have to go to their Myths & Legends page here to find a mention, amongst tales of King Arthur etc.)
The subsequent Abbey for centuries was the largest and most splendid in Britain. It's also an international tourism destination because King Arthur is supposedly buried on the grounds (a plaque marks the spot), and there are other associated New Age mysteries, which are catered to by a thriving counterculture establishment offering workshops, tours, beads, spiritual guidebooks etc. (BTW, the famous Glastonbury Festival of rock music - " the longest running and most pre-eminent music festival in the world" just uses the name for its counterculture resonance - it's held some miles away. There isn't one this year, though you can see Glastonbury:The Film, a retrospective compilation documentary released in April.)
The Glastonbury Pilgrimage is a church-sponsored affair, though the events are officially 'open to everyone.' Events begin at noon or later to allow 'day-tripper' pilgrims time to get there (in fact some pilgrims walk all the way from their home towns). The ceremony includes a procession to or from the town's distinctive landmark, The Tor (the volcanic spur in all the tourism photos showing the ruined St Michael's Chapel).
Note if you type 'The Glastonbury Pilgrimage' into Google, The Glastonbury Pilgrimage site which comes up first is a 'cobwebsite,' abandoned in 2002 (check the date). The Pilgrimage is not now held on the 2nd weekend in July, but in June. The 2006 event is the weekend of June 18-19. It's always a two-day affair, but there are two rival pilgrimages, held on separate days because they involve prayers and masses and other denominational arrangements. The reason for this is the Abbey was originally the Catholic's major establishment in England, pre-Canterbury, but became an Anglican one in the 16C Reformation. The Anglican (i.e. Church Of England) pilgrimage is on the Saturday, and the Catholic one on the Sunday. The first is organised by the Clifton Diocese (Clifton is the old district of Bristol - it's for example where local DVC/HBHG fans go to see the Templar graves). Information on the CoE one is on the official Abbey site here.
The theme of this year’s Pilgrimage is "Mary, Woman of Hope". TDVC fans and conspiracy theorists into the idea the Church airbrushed Mary Magdalene out of its history may like to know that, on the one hand, references to the town as the home of the Shrine of St Mary, Our Lady of Glastonbury (a shrine being a traditonal pilgrimage destination) are not to Mary Magdalene, but the Virgin Mary Mother Of God (meaning Jesus) - which does seem to have been the original dedication of the Old Church. (See The Glastonbury Shrine site on this, here and here.) On the other hand, however, the church of St Mary's is situated on Magdalene Street......
Glastonbury being a destination for people on all kinds of quests, the official church pilgrimages are just a small part of the town's summer-events programme, detailed at Glastonbury Online, which also includes the 16th Glastonbury Symposium on crop circles [July 28-30], The Goddess Conference for women "Celebrating the Great Mother at Her Festival of Lammas" [Aug 26], The Glastonbury Abbey Extravaganza (this year supplanting the more famous music festival) [Aug 4-6], a Children's Festival [Aug 11-14], The Tor Dance Festival [Aug 18-20], and a 'Shamanic Gathering UK' [Aug 25-26].
If you want to more about Glastonbury as a multi-cultural pilgrim destination, the Open University made a film in 2001 called The Glastonbury Tales which has its own sub-site online, and which recognises it as Britain's first church, established around 64 CE by Joseph of Arimathea.