Spinventory

In your videogame the inventory screen uses the actual in-game 3D model of the item in the inventory display. Makes double-use of the effort and shows off the work. The problem is that by itself and close up the model doesn't look very good. Especially in older games, where it might not even be recognizable.

The solution? Set it spinning! Shows off your spiffy 3D model and your game engine. Have it pulse toward the player for extra spiff.

The spinning inventory item can be split into two types, automatic and manual. Manual spinning is sometimes necessary to examine items for information necessary to progress in the game.

Some games combine both automatic and manual spinning. Allowing the player to stop the rotation by applying reverse spin, or doubling the speed.

Some games may actually use this for a puzzle--you have to spin an item to find something written on it, for example.

Sometimes items may be arranged in a 3D ring which can be rotated to bring different items to the front. Tomb Raider: Anniversary brought this technique back from the original series of games. The individual items may still spin.

There is also a videogame phenomena when dropped items hover a little way above the ground and spin for no adequately explained reason.

Subtrope of Everything's Better with Spinning.

Action Adventure

 * Beyond Good and Evil: Inventory items can be rotated manually. This is important for finishing the game, as the randomly-generated passwords for some safes and doors are written on certain objects.
 * Obscurish action game Sphinx and the Cursed Mummy does this with your monster book--including the pulsing.

Action Game

 * The Lupin the Third PlayStation 2 game had spinning items. At least one puzzle required you to spin an item to find a code.

Adventure Game

 * King's Quest VII. The models look quite primitive, but at least by rotating them you can find hidden details.
 * It's also the only way to get past certain puzzles, and the Good Ending. Good luck ever figuring out that last one, though, since the special fix-everything button on the final item is limited to a single pixel that can only be accessed by turning the item to a specific angle and has no obvious change until you rotate it back around.
 * Quest for Glory V
 * Escape from Monkey Island
 * Phantasmagoria
 * Ripper
 * Still Life
 * ...actually, a lot of adventure games do this.

Fighting Game

 * Trophies in Super Smash Bros Melee and Brawl spin slowly in your gallery, and can be rotated manually.
 * In a similar vein, a recent update to the 3 DS' Street Pass Puzzle Quest allows you to view 3D models of the completed panels as you complete them, including a steadily-rotating scene of Link from Game/Twilight Princess and a "trophy" of Bowser, Mario and Luigi. Weirdly, you can only rotate them manually by a very small amount.
 * Soul Calibur 2 had this for the weapons gallery, when you could see them and a short bio piece.

First-Person Shooter

 * Golden Eye 1997 007 for N64
 * Metroid Prime 2: The logbook.
 * Rather than just showing the model of the item, Team Fortress 2's loadout screen lets you spin a model of the character equipping each item.
 * Serious Sam has bouncing, spinning items on the ground.

Hack and Slash

 * In some of the Dynasty Warriors games, you can examine your character models up close and rotate it, as well as switch out the alternate outfits.

Light Gun Game

 * The Attract Mode for Target: Terror, a Light Gun game, did this for its powerups, along with some tech specs. In-game they would spin too.

Mecha Game

 * Armored Core has been doing it from the first game.

Platform Game

 * Ratchet and Clank Up Your Arsenal does this with trophies. Joystick controls let the spinning be either stopped, or sped up. The trophies can also be spun vertically.
 * Tomb Raider: Anniversary does this with relics. Again, joystick controls can affect the spin.
 * Lara's inventory is on a ring, which is spun manually to bring different items to the forefront. The items pulse, but do not spin themselves.

Role Playing Game

 * Inventory items in Star Ocean the Second Story.
 * Dropped in the PSP remake, as people would no longer be impressed with spinning 300+ identical swords, bottles of wine, plates of food, etc., and the models wasted a lot of space.
 * The Dark Cloud games could present weapons like this for Item Crafting purposes.
 *  Final Fantasy VIII has a "Scan" ability. Cast "Scan" on an enemy, and you'll get a rotating 3D image of the enemy, along with stats, HP, strengths and weaknesses.
 * Though, knowing their audience, Squaresoft doesn't let you tilt the camera up or down when the target of the spell is a skirted female like Selphie...
 * The inventory popups in Vampire: The Masquerade Bloodlines does this. You can even click-hold and drag to control the item's orientation. This also applies to the character screen.
 * In the case of the character screen, it can even demonstrate the Jiggle Physics.

Shoot'Em Up

 * The Continue screen of the original Star Fox game would show off a variety of enemy ships and items, as well as a high-polygon version of the Arwing, on a grid. You could leave them spinning automatically, or control the pitch, yaw, direction, and speed of the rotation. You could even make the models leave after-images (an effect used in-game by the Phantron.)

Simulation Game

 * Viva Pinata: Pocket Paradise does this in the encyclopedia screen for all the items and seeds. It doesn't do it for the plants and decorations, though, since they're sprites and not polygons.
 * The PS2 Ace Combat games have the camera rotating above/around the planes in the hanger as you mull over just how you want to blow your enemies to kingdom come. Most games also allow you to control the camera.
 * Ace Combat 2 for the PS 1 was the one that started it for the series. You also got to even view the enemy's paint schemes, as well as enemy exclusive aircraft like bombers and helicopters through it as well.
 * Super Power had an especially egregious use: the design screen had spinning models, when there wasn't any other use of 3D in the entire game(units were just symbols on the battle screen).
 * Many of the X-Wing series of games had a section where holographic (and fully-spinnable) replicas of Rebel, Imperial, and neutral craft were available to view.

Stealth Based Game

 * Metal Gear Solid 3 Snake Eater and Metal Gear Solid 4: Guns of the Patriots. Spin Snake enough in the third one and he'll vomit.
 * The Thief series does this.

Survival Horror

 * Alone in The Dark (1992), the first three games. Very possibly the Ur-example.
 * Eternal Darkness: Sanity's Requiem had the items set in the pages of a tome but you can examine items and rotate them. It's needed for some of the puzzles.
 * Same thing for the original Resident Evil where certain clues were hidden from view until you turned the item around. Particularly annoying that the character wouldn't notice the type of key he just picked up without you physically looking at the other side in the inventory.

Third-Person Shooter

 * Not so much Spinventory as a shrewd design decision, but the weapons in Red Faction Guerrilla's multiplayer hover above the ground and spin at a leisurely pace with a neat little shine rather than obey the laws of physics like their single player counterparts. According to the Devs, this was because people couldn't find the damned things amidst the chaos of a world where buildings are made out of polystyrene and biscuits.

Visual Novel

 * The fifth case of Phoenix Wright Ace Attorney.
 * Also Apollo Justice Ace Attorney, being that the 5th case of Phoenix Wright was basically a preview of AJ's features.

Wide Open Sandbox

 * The 3-d Grand Theft Auto games would do this with pickups, ranging from cash to heavy weapons.
 * In The Godfather: The Game you can manually spin weapons in a certain menu screen, but only horizontally.
 * Weirdly enough, The Elder Scrolls V: Skyrim introduced the adventure game rotate-item-for-clue variety to the series.

Other

 * The Nintendo 3DS main menu. Most menu items either spin like a turntable or rotate slowy. Some of them can be spun real fast by flicking the analog stick or blowing into the microphone. Wonder why the Miis don't fly off in Streetpass Mii Plaza when this happens.
 * The collected items in Katamari Damacy