Online text manipulation tools: copy and paste text into the broser, then tinker with it in various ways (eg. randomise lines of poems, merge lines, reverse text etc)
Use IPA (International Phonetic Alphabet) characters without having to remember complex codes or multiple keystrokes. Just pick the characters you need from the chart, and copy & paste them into your own document.
I like the way this site categorises the semantic relationships between words. Exploring these concepts with students, especially when discussing language change, can be very instructive.