Something that happens sporadically doesn't occur with regularity, but rather periodically or occasionally. You might meet sporadically with your cousins, usually on minor holidays like Memorial Day or Flag Day.
Sporadically comes from the Greek word sporadikos, meaning scattered, with the root word spora, which means sowing. Imagine sowing seed by scattering it, and you'll get the hit-or-miss sense of sporadically. There is no pattern to the frequency of an event that occurs sporadically. Working sporadically is hard because you lack a steady income and never know when you'll be busy, but traveling sporadically can be fun.