A free-as-in-speech as well as -beer textbook of data structures, covering a great range, including some I hadn't heard of before. Here's the full list: ArrayStack, FastArrayStack, ArrayQueue, ArrayDeque, DualArrayDeque, RootishArrayStack, SLList, DLList,
SEList, SkiplistSSet, SkiplistList, ChainedHashTable, LinearHashTable, BinaryTree, BinarySearchTree, Treap, ScapegoatTree, RedBlackTree, BinaryHeap, MeldableHeap, AdjacencyMatrix, AdjacencyLists, BinaryTrie, XFastTrie, and YFastTrie

sparklines in your terminal window. Simply give it a comma or space-separated list of data values, and it'll generate an ANSI-graphics sparkline chart. Brilliant! (via mjd)

'an open source JavaScript library that produces produces interactive, zoomable charts of time series. It is designed to display dense data sets and enable users to explore and interpret them.' quite pretty

good HN thread on better charting tools in JS