Of course, La Universala Kongreso de Esperanto is the highlight of the Esperanto calender, but there are many other events as well.
Most countries hold a national conference.
This is where promotion of Esperanto is discussed, but it usually provides a good opportunity to practise your Esperanto as well. It offers free overnight accommodation in homes of Esperantists, so you can tour foreign countries on a very low budget. The main thing, though, is that you get to know the local people, using Esperanto. Membership is free if you speak Esperanto and can offer your own home as well. Otherwise there is a small charge.