HexsweeperThis game is like minesweeper but instead of having square tiles, the tiles are hexagons. For those of you who don't know minesweeper, the game works as follows: Below some of the tiles, there are mines. If you left click on such a tile, you lose (don't worry, there's never a mine below the first tile you click). To win, you have to left click all the tiles below which there isn't a mine. You can right click tiles to mark them if you suspect there being a mine. The number inside a tile denotes how many mines there are in the adjacent tiles. This helps with locating and avoiding the mines.
Hackernews collapsible commentsThis is a Greasemonkey and Tampermonkey script (tested on Firefox and Chrome respectively) that makes comments collapsible on https://news.ycombinator.com.
If you click on the little plus/minus sign, it expands/retracts the entire subtree of the comment. If you click on the comment itself, it expands/retracts only the direct children of that comment. The orange Hackernews bar now contains a button to expand or retract all comments. The number below the plus/minus sign is the total number of child comments this comment has. Instead of seeing one top comment and dozens of semi-intelligible responses, you now see all the top comments while the responses are retracted by default. You will be surprised by how pleasant reading Hackernews comments becomes.