Since 1969 I use APL, mathematic language interpretable by computers.
Every year there is an APL international congress. For odd years in USA or Canada, for even years in Europe. Since 1985, I have gone to those congresses and paid myself because the France, on the contrary of all developped countries, such Canada, USA, UK, Denmark, Finland, Germany, Australia, Japan, China, Italy, Spain, Russia, and I skip!, does not know this very powerful language but some happy initiated ones as me.
Here are some congresses where I was: