Example map on how to make an armed grenade fall out of a vent in Spirit.
You can simplify this using a monstermaker to spawn the armed grenade entity, if you can figure out what it's called, that is.
Thanks goes to The Mighty Atom/Muzzleflash, Chickenfist, and fold for help, advice, and inspiration.
And thanks Cstriker! I'm glad I can actually help someone! (I'll take what I can get rating-wise, too)