The following two links to Cambridge University Computing Labs pages were provided by Silas Brown - ACCU's Disabilities Officer.
Group Projects suggestions. Follow the link and then use the link to the briefing booklet.
Project Suggestions. Go there and follow the links for a rich source of programming project ideas.
Mining Oxford University Computing Labs pages for collections of project ideas is somewhat harder than it is for Cambridge University. To start with several good collections are in Postscript files which makes them somewhat harder to access but nonetheless it is probably worth the effort if you are looking for tough degree level projects. The simplest start point is Oxford University Computing Lab's search page and then search for 'projects'.
Link and information provided by Thaddaeus Frogley
You may find the problems set for the Programming Fun Challenge (PFC) to be useful/interesting.
The general consensus seems to be that the problems are supposed to be "solved by a skilled programmer in an hour", but they vary greatly from this ideal. Some would be perfect study problems for a student. Some are much too hard. All come with a selection of solutions.
If you know of a good source of project ideas please email me the details. The general quality of this resource depends very largely on the small efforts of many readers who become contributors.