It is good to be aware of some nasty bugs regarding DBMS_LOCK.SLEEP, particulary if you want to have relatively accurate sleeping intervals or if you want to sleep for a longer period of time (sey for more than half an hour). Those bugs are described at the "BUG Warning" of the following article:
Those bugs were present in all release up to 8i (If I remember correctly I last checked and reported them to Oracle as bugs on 8.1.7, I haven't took my time to test if they have been resolved on 9i).
ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?