Frank Zappa's extensive output can seem quite intimidating to the uninitiated so here is a little help. I'll make it simple; start with Apostrophe.
Apostrophe is perhaps Zappa's finest album. It features all the essential ingredients from his earlier LPs but the blend is far more palatable. Zappa's voice on this album has a wonderfully deep, rich and very satisfying timbre effectively translating his unique humour and charisma. His lyrics paint such clear comic strip pictures in your mind that it's really worth taking the time to listen to this album properly and watching these pictures pass by your mind's eye.
And friends, if you already love Zappa, look up my recent discovery Discharge Lounge, a very tuneful and humourous live band who have some great recorded work out there too, you'll find them on a site called bandcamp:)