I didn't take the golden cup in the bazaar, but it makes elite items (unlocked through Bazaar level 3) much more likely to spawn.
The refreshment boon is a 50 piety boon from Mystera that restores half your mp when you convert a glyph.
I assume you mean the one behind the wall? Those are secret subdungeons. If you ever se a square blocked in on all sides, try to get to it. They're great.
The whupaz potion is a witch 3 potion whose effect is never to be put on the forums. NEVER! And it's super great for vicious dungeons. Although I easily could have won without it, as I had 4 schadenfreude potions.