The 1911 and 1901 Censuses of England & Wales are available to search and view free of charge this Easter at Ancestry.co.uk. The 1901 Scotland census is also included.To take advantage of this offer, you'll need to register with your name and address at Ancestry, but you don't have to give credit card details.
The offer lasts until midnight (GMT) on Monday 1 April.
Incidentally, Ancestry has added a search function into the Northern Ireland Will's Index. This Index is already free to search and view on PRONI, along with 93,338 images of actual wills 1858-1900.