Plasma balls, plasma lights, and neon signs.

All of these lighting fixtures use a transformer in much the same way a violet wand does.  In fact, plasma balls and other plasma lights have the same type of visual display that a violet wand does.  There are some neat tricks that you can do with plasma lights, like light up nearby fluorescent tube lights, or get the sparks to travel.  But you don't get any feeling from them, and you can't use violet wand tools and accessories or any violet wand techniques with them. 

Verdict:  Use them to create some ambience in your dungeon.  Or your college dorm.