I started 12 years ago; it's like learning a language. I perform the English style of change ringing, which means the sound is not regular tune music, but involves ringing methods - sort of mathematical patterns - to a constant rhythm. The unvarying rhythm and limitation to a diatonic scale means it doesn't hold an audience's attention, unlike orchestral music, but the effect on the ringer can be mesmerising.
I am a member of a ringing society with records back to 1630, so it combines tradition with mental stimulation. Lots of change-ringing music is very mathematical, and indeed lots of maths in the area of group theory was discovered by ringers.
There's teamwork, a great sense of community and a lot of physical effort. I once rang two handbells for 72,000 changes, which took 24 and a bit hours. The rhythm brought about a trancelike state. Once it had started, it couldn't be stopped. I ate by bobbing down and picking up food.
It absolutely makes me happy. There's a perception that ringing is for misfits, but that's not true - historically, ringers have been an ungodly bunch who drink too much beer. Some of that continues. It appeals to people who are excited about mathematics, and to those who love the beautiful regularity of music. It can be aesthetically pleasing, but ringing a loud instrument can also just feel very, very good.