Locked chest

Locked Chests (also known as Steve Co. Supply Crates) are a block that were added in Minecraft Beta 1.4. Every chunk generated on April 1 had a small chance of having a locked chest in it. Clicking on the chest would bring up a screen (as shown in the gallery), and clicking on the "Go to Store" button will forward you to the Minecraft Store, an April Fools' Day joke. The chests emit light at level 15 and are indestructible by hand or with a tool, but can be removed by explosions (which may drop them as an item, allowing them to be picked up). Notch planned to remove them at midnight, but didn't due to illness.

Items "Sold"
Eight "items" are "available": As well as three "Coming Soon" items (Priced at $75, $7, and $1499) and a "Regular Padlock" for $8.
 * Steve Co. Supply Crate Key ($3)
 * Steve Co. Supply Crate Key 5-Pack ($18)
 * Miner's Helmet ($21)
 * Name Change ($99)
 * Creeper Saddle ($42)
 * Secret Griefer Identity ($155)
 * Enlargement Pill ($2)
 * Response From Support ($494)

Trivia

 * Locked chests are a reference to the Mann Co. Supply Crates from Team Fortress 2, where a key must be purchased for $2.49 in the in-game shop called Mann Co. Store in order to open the crate.
 * The store page uses the font tf2build.ttf from Team Fortress 2. The font is downloadable from here.
 * Clicking on the proceed to checkout button triggers a screamer in which a Velociraptor from the movie Jurassic Park will growl loudly and fly across the screen.
 * Entering items totalling over $10,000 into the cart causes a window pop-up asking if you are prone to seizures. Entering OK makes the screen start flashing. When first released, there was no seizure warning label, Notch later implemented it to avoid lawsuits and posts on the forum. But there is one registered seizure case in Russia. No proof by the way.
 * This may have been what Notch was talking about in his Twitter post about a "silly secret project".
 * Locked chests can generate in mid air or in the tops of trees.
 * It is more cost efficient to buy five Steve co. supply crate keys than it is to buy a five pack.
 * If destroyed by TNT and collected, locked chests can be used as fuel in a Furnace like normal chests. They burn for 15 seconds each.
 * Locked chests can be placed next to each other to form a 2 block long chest like normal chests do. These two chests are still however "locked".
 * To get the flashing colors in the Minecraft Store, the "purchase" must total over $10,000; $10,000 exactly will not work.
 * On April 2nd (the day following April Fools), the store had the addition of a multicolored banner which read '♥ April Fools! ♥', accompanied by a midi instrumental of Rick Astley's 'Never Gonna Give You Up'. Tobias Mollstam stated that this was the "best script he's written to date".