cron when not su

[utzoo!decvax!pur-ee!davy]

Does anybody out there know of an existing command which will behave like
cron(8), in that it will execute a command every {hour,day,month,etc.},
but that you don't have to be su to run (i.e., I can't modify crontab).

I seem to remember somebody mentioning "at" or "calendar" in this context,
but the manual doesn't mention anything about it.

Please MAIL (that's "r", folks) responses to:

		{decvax, ucbvax, ihnss}!pur-ee!davy

Thanks,
--Dave Curry