Pet show
A pet show can be very successful as a fund raising event. You need a venue which will allow animals(!) and the venue must provide sufficient space for the all the pets to stay while the event is being held. You will need to have plenty of water available and to be able to easily clean up any mess that is made.
A show area is required which is fairly separate from where the animals are.
Depending upon the pets being shown, there will need to be predetermined classes of animals.
The main point is to have a fun day