h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have found that soy sauce makes the ideal base for a marinade. Mix a generous few glugs of soy with a pinch of sugar and some herbs and spices, then pour on to a dish or plate with a high lip. Stick meat and veg onto skewers (if wooden sticks, you must soak in water for 20 minutes beforehand to stop them burning).
A particular favourite is to add a little dry sherry to the mixture and skewer long strips of chicken breast in a running stitch pattern before marinating. This makes a great basic teriyaki.

Just soy on its own is fantastic on joints of chicken. Marinade for a while first, then mix some soy sauce with oil to baste them with.

Soy sauce also works well as a base for a marinade for Tofu (which really need some sort of marinade) so you can please all you vegetarian friends, check out the Vegetarian BBQ thread for some recipe ideas.