An RFE (Real Flight Event) is an event where the real world airline schedules of an airport are followed during the time of event by all the participants..
Many airlines fly inside London Heathrow daily. So, by participating of the event, you'll have the opportunity to see different airlines on the airport.
During the event, all ATC positions possible are staffed to provide ATC service to the pilots.
Every IVAO member can join in the event by making his/her flight. So, the RFE is an opportunity to meet new people from different cultures.