note: This didn't work on OpenBSD. I found a perl version in netbsd's ports collection and stole a copy for my own use.

Using remind's RUN directive and echo to pipe reminders to commands.

rem2pdf is a Perl program that takes the output of "remind -p" and
produces a PDF calendar. See "man rem2pdf" for details.

(not included in all distribution packages of remind)

text-based front-end to Remind

Note: last known working copy according to mailing list.