looking for a program like DOS' Today

There is a program called Today.com, written for the DOS operating system that reads a text file that has date info on the first line (when/how long to show it, etc.) It is easy to configure, for instance I can say 'show this line every month on the 3rd, etc. Is there something like this for Linux? I have it pop up when I boot the computer. John Sowden American Sentry Systems. Inc. 1221 Andersen Drive San Rafael, CA 94901 U.L. Listed Central Station Alarm Service Serving the San Francisco Bay Area Since 1967 mail@americansentry.net http://www.americansentry.net