In English universities, the extra-curricular representative structure for students is called the Students' Union.
University College London (UCL) Union website
The objects of the Union are the advancement of education of Students at UCL for the public benefit by:
4.1 promoting the interests and welfare of Students at UCL during their course of study and representing, supporting and advising Students;
4.2 being the recognised representative channel between Students and UCL and any other external bodies; and
4.3 providing social, cultural, sporting and recreational activities and forums for discussions and debate for the personal development of its Students.
The annual party for students to raise money for serious causes is called Rag Week, and is generally marked outside the campus in the university town by students in various fancy-dress outfits with buckets collecting money. Some, like Imperial College, London, do quite a bit more.
To further its objects, but not to further any other purpose, the Union may:
5.3 support any RAG or similar fundraising activities carried out by its Members for charitable causes, including the provision of administrative support, banking facilities and acting as a holding trustee of any funds raised;