You might not be able to get a thunderstorm to show up for your practice sessions, but if you just need a good shock--

-- You know those tabletop generators they use for physics classes? That make your hair stand up if you touch them? What's it called, van der, van de something.

[He doesn't know where he might have run into a tabletop generator like that, but, he reflects, if it was in school apparently he slept through the parts of physics class that didn't involve cool sparks. Oh, well.]

They'll generate a pretty solid spark if you need one to practice on.