A simple terminal-based open source Spritz-alike.
This command line filter shows input text as a per-word RSVP (rapid serial visual presentation) aligned on optimal reading points. This kind of input mode allows reading text at a much more rapid pace than usual as the eye can stay fixed on a single place.
cat tea.txt | ./speedread -w 250
The default of 250 words per minute is very timid, designed so that you get used to this. Be sure to try cranking this up, 500wpm should still be fairly easy to follow even for beginners.
speedread is slightly interactive, with these controls accepted:
You can connect mutt with speedread by putting a macro like this in your ~/.muttrc (or pressing ':' in running mutt and pasting it):
macro pager R "<enter-command>set pipe_decode=yes<enter>v|grep -v '^>' | ~/speedread/speedread<enter><enter-command>unset pipe_decode<enter>q" "speedread"
Then, just press R when viewing a message. Unfortunately, it does not work with non-ASCII messages (probably due to mutt limitations).
Not sure if I will ever get around to these...
Check out also OpenSpritz or spritz-js if you want to get this functionality in the web context.