From the Super Mario Wiki
Roulette Blocks are types of blocks first found in Super Mario World. They are blocks that contain items that scroll in a roulette. The item the block displays while the block is hit is usually the item that comes out.
Super Mario series
Super Mario World
In Super Mario World, a Super Mushroom, Fire Flower, Cape Feather and Star can come out of a Roulette Block. However, once Mario or Luigi releases the item out of the block, it bounces around like a Star, and it still changes from power-up to power-up. Mario or Luigi can grab the power-up at the right time to obtain that power-up's effects.
Super Mario Advance 4: Super Mario Bros. 3
New Super Mario Bros.
Roulette Blocks reappear in New Super Mario Bros., but with a few differences. They are blue instead of transparent, the items scroll much faster, and they do not continue scrolling once they pop out - Mario must hit the block at the right time to make that item pop out. The possible items found in these Roulette Blocks are Super Mushrooms, Fire Flowers, Stars, Mini Mushrooms or Blue Shells. Also, red Toad Houses contain giant Roulette Blocks (that contain the same items as the ones mentioned, besides the Star) which Mario can use to hold an item in reserve.
New Super Mario Bros. Wii
The Roulette Blocks from New Super Mario Bros. also appear in the sequel, New Super Mario Bros. Wii. The blocks are yellow this time, and they contain items such as a Super Mushroom, 1-Up Mushroom, Star, Propeller Mushroom, or Penguin Suit.
Super Mario 3D Land
The next appearance of Roulette Blocks is in Super Mario 3D Land, as transparent glass blocks, like in Super Mario World. A winged Roulette Block can be found in some levels.
New Super Mario Bros. 2
These blocks return in New Super Mario Bros. 2, with the same design as in Super Mario 3D Land. In addition to the normal ones, yellow numbered Roulette Blocks also appear, which produce coins instead of power-ups. When Mario hits the block, coins will pop out in the amount shown on the block as it was hit, either in single coins or 10 Gold Coins. The numbers that appear are 5, 10, 30 and 50, with 50 appearing only once per interval. In the Rainbow World, 50s are more often in the coin Roulette Blocks, including the larger one with a maximum number of 100 coins, instead of 50, and do not have a 5 or 30 in it..
New Super Mario Bros. U
Roulette Blocks also appear in New Super Mario Bros. U with the same functions as before, though now it has the same design as that of New Super Mario Bros. Wii. Roulette Blocks now have the possibility of generating a Super Acorn, an item introduced in the game.
Super Mario 3D World
Roulette Blocks reappear in Super Mario 3D World with the same function as Super Mario 3D Land. They now have the possibility of generating a Super Bell, an item newly introduced in the game. Roulette Blocks also appear in the jackpot machines, though the player gets no item if they hit it. Instead, there are four big ones and the player has to match the image on all of them to earn Coins and 1-Ups.
Super Mario World television series
A Roulette Block appeared in the Super Mario World television series in the episode "King Scoopa Koopa". After Princess Toadstool spots the Roulette Block and suggests that Mario should hit it, he hit the block and obtained a Cape Feather.
Mario Party 9
These blocks reappear in Mario Party 9 in the Sock It to Lakitu minigame. Here the items are a Bullet Bill, two Bullet Bills, three Bullet Bills and a Spiny Egg. The Bullet Bills damage Lakitu while the Spiny Egg may damage the player.
Mario Party: Island Tour
Roulette Blocks reappear and generate items.
Names in other languages