I like to back up the data on my laptop computer as often as possible, just in case I have trouble with it. I have some large files on the laptop that prevent me from scheduling an Internet backup to my home machine, so I have written a script that reminds me to periodically plug in an external USB drive; then upon clicking continue, the reminder script runs my custom backup script.
I use the at scheduling daemon to schedule the backup reminders, and xdialog to present a graphical interface for the reminders. The script presents a GUI that prompts you to prepare for your backup (plug in your USB drive, bring up your network interface, etc.).