I was parsing some Netbackup logs today, and needed a way to convert the time since the epoch into a human readable string. A while back I read about the various forms of input that can be passed to the GNU date's "-d" option, one of these being the time since the epoch:
$ date -d @1263408025
Wed Jan 13 13:40:25 EST 2010
This solved my issue, though unfortunately it's not super portable. Food for thought.