There are hundreds of imaginative activities that will raise funds for your event. Charities Information Bureau (CIB) has an A-Z list of ideas. Just make sure that your event is legal, as for example there are regulations about running large raffles.
Some events take a lot of work and investment to organise. You need to look carefully at how much money an activity is likely to raise and decide if the effort isworth it or the risk too great. Charities Information Bureau (CIB) website has ideas for fundraising. http://www.cibsouthandwest.org.uk/publications.php
Visit the Grants section for information about funding sources.