Actually powergaming has it's place in P'n'P too. The mantra is: All actions must fit with the acting character and the situation described.
Also there are many ways to "cheese" out in P'n'P sessions, if you have a Game Master with a sense of humor.
Here is an example of a P'n'P 3rd ed cheese tactic:
We are a three man party of a sorceror (me), a mage/cleric and an orog fighter. We are being hunted by another party of adventurers desiring the same artifact. Our orog friend has recently been incapacitated by their thief with her Wand of Fireballs.
We are standing in an underground corridor and in front of us their obscene powerhouse of a half-ogre/half-dragon barbarian (can anyone say munchkin?) comes charging.
We are already pretty cornered since their thief has set up a sniping position with her wand. Going head to head is not an option and we can't really hurt the thing with spells either (an ugly combination of natural resistances, items and barbarian immunities).
I am desperately trying to come up with a nifty spell, and then it hits me. Monster summoning! None of the monsters would be able to fare in close combat with our adversary, but that's not the important thing. I had my eye on one specific creature whose vital statistic was neither armor class nor hitpoints but size: The celestial orca whale! I consult the book and our DM and it's clear. I designate exactly where the monster will appear (within the spell range of course). I chose it to appear directly above the ogre/dragon abomination.
But doesn't monsters appear standing on the ground? Well, not if they are flying monsters otherwise it would be stupid to summon arrowhawks (birds with four wings and no legs) for example. The celestial orca is a flying creature (it has huge angelic wings) and being a whale it does not have any legs to stand on. Under any conditions it would be stupid to assume that the creature would appear on the ground. The only logical places for such a creature to appear would be in midair or suspended in water. Since there is no water here the monster must appear in midair, all logic dictates that, and the spell description says that I can decide exactly where (within the range).
Now comes the clou: The tunnel is just big enough for the monster to fit, but it is not big enough to allow the whale to spread it's angel wings out fully. (The creature is huge and what kind of wingspan goes with that?
).
The train of events is: The celestial orca appears in midair directly above the half-ogre/half-dragon. It fails to remain airborne because there is not enough space for it to spread it's wings. The orca falls dealing a large amount of instant hit bludgeoning damage to the half-ogre/half-dragon (one of the few things it wasn't resistant to). The amount of damage is enough to incapacitate the ogre/dragon and he is smothered to death as the orca waddles around trying to get out.
This was clearly not what was intended with this spell, but it worked.