Hell, why stop the RP for the fights, Thundespire and the PCs are battling a bunch of Far Realm abominations, actually Foulspawn Berserkers, Manglers and a Grue- only the Foulspawn know one of the PCs of old, and the terrible things he did.
So they're (or I am) shouting out things which make no sense (except to the one PC, although now some of the other PCs are getting sus), the PCs are screaming things back because... well that's what the situation calls for.
Also in the chamber is the dead spirit of a Dwarven Warrior (victim of the same ex-naughty PC), who's putting up a constant chatter and undermining said PC.
Which is further arousing the suspicion of the other players.
Then another dead Dwarf turns up (same PC's ex-best friend, also victim of the same ex-naughty PC) then the two Dwarf ghosts start to argue, with the PCs unsure as to whether they should be attacking things or trying to listen to what the ghosts have to say, more out loud speculation and awkward questions.
Meanwhile on the walls in the area the PCs are fighting are a bunch of Demonoid Faces- with gaping maws, through which the Foulspawn initially teleported into the attack.
The Demon faces are hungry- calling for CRISPS, and POP, and CHEESE SANDWICHES... with PICKLE.
The Wizard takes it upon himself to help out the starving Demon Maws and throughout the fight chatters and calls out to the Demons, and feeds them as he goes about his business. The Demons refuse to teleport any more the Foulspawn in (as per module), and after singing three or four verses of the SPAM song cough up a Foe Stone, one of them had a speech impediment throughout.
I kinda know what I'm doing before I start but once the players have got the thread of the thing I just tell them to keep pulling to see how far it goes.
I stop fights approx once every two sessions, for more of the same, so even in the Pyramid of Shadows the players are getting some RP.
Love it.
Cheers PDR