Put props to work
Like some of the previous posters, I used lots of props in my last campaign, including various types of papers, spellbooks, and magic items. (I used minis with 3D terrain etc. as well, but I don't really count those as props.)
One thing that I really enjoyed doing was making the props serve a function in the campaign. In other words, the players really had to use their noggins to figure out the prop. Here are some examples from my last campaign.
- During the game, the players found a foot-long piece of shiny metal, bent in two places. (I actually used 1/4 thick wood, spray-painted silver.) I handed them the object. They didn't give it much thought, really. Later a sage confirmed for them that it was only half of a fully-assembled object. So they ventured out and found the second piece of the object, which looked exactly like the first, a foot-long piece of bent metal. When the players were fiddling around with the two metal pieces, and the brought them together in a particular way, THEY STUCK! (I had drilled holes in the wood and glued magnets in there, then covered them with cardstock and painted over it.) They toyed around some more and figured out that there was only one way to orient the pieces so that the magnets attracted each other.
- During the campaign, the players had acquired a number of maps. One in particular showed lands that they needed to get to, but for the life of them, they didn't recognize any of the other features on the map, so they didn't know which way to go. The game continued, and a couple hours later, one of the players finally announced, "I've got it." He showed the other players how the map fit (and slightly overlapped) to a map of their current location. A similar feature on both maps had been gnawing at his subconscious until he finally made the connexion.
- When searching the residence of an enemy, the players found about 50 tiny scraps of torn-up parchment. They didn't spend too long trying to piece these together before the spellcaster remembered he had a Patternweave spell in one of his spellbooks (another real prop). When he cast it, I gave him an assembled copy of the parchment to look at for as long as the spell lasted in real time (like 5 minutes IIRC).
- Magic in my campaign is a little more arcane than in most D&D games. In order to cast a spell, the player had to actually know the name of a circle of power for the appropriate magic school, along with certain other secrets. I didn't formally announce this fact to the players at the beginning of the campaign, since none of their characters had actually studied magic. So the player was literally learning right along with his character, including making various mistakes and learning from them, too. ;-) When he found a necklace of bone fragments, each carved with a different circle of power (and their names on the obverse), I handed him the real prop and he was very excited.
- One of the challenges in the campaign was defeating a ghostly NPC at a game similar to chess in order to receive a key. During the session, I brought out the board and pieces for the game, and explained the rules. Then we actually played the game (within the game). When the ghostly NPC was defeated, he lifted a section of the gameboard to reveal the (real) key hidden within.
I really enjoy it when the players actually figure things out, as opposed to them just rolling a die and asking if their character solves the puzzle. ;-) I had a number of other props in the game, a whole footlocker full of them actually, but the ones above are the most obvious examples of those that serve as more than just props; they're game elements in themselves.
Also, another piece of advice: make sure you throw in a fair number of mundane props, too, just so players don't say "if it's a prop, it must be important."
ironregime