Check out some examples from quickscript-extra, and some starter ideas below.
- csv->sexp or json->sexp (use existing libraries)
- sort a list of numbers from the selection
- lexer with split string
- spell check or spelling fixer (more complicated)
- beautify code (using pretty-print for example)
- ASCII art!
- Add Windows and/or Macos support to git. (maybe use open-terminal as a starting point?)
- Post the current selection to the Racket Slack. (tweet is an example of using a web api)
- Make a game? (maybe use 2htdp/universe or lux?)
Looking for more ideas? What about porting some of emacs scripts and vim scripts?
When you have an idea...Getting started for the impatient is a good starting point.
- abstract-variable: Create a variable from the selected expression video
- extract-function: Extracts a block of code out of its context and generates a function and a call video
- indent-table: Indent rows on double-space-separated colums video
- ROT13 encoder/decoder - This was the first entry!