High voltage is a weird and fun area of electronics that a lot of geeks get into via building Tesla coils. Ive built a few HV things including a few tesla coils (pro-tip: a caulk tube makes a great baby secondary) and a can crusher with a 14uF 40kV pulse capacitor. I also briefly built a small 10x Cockcroft–Walton generator using the neon sign transformer from my Tesla coil but the caps failed rather quickly from abuse.