Joshua at JD Bliss alerted me to their new “Attorney Work Life Balance Calculator” that will (according to the site) help you determine:

• how many hours you must spend in your office during the week (Monday through Friday) in order to meet the billable hour requirements of your firm (taking into account vacation, personal and other "days off"), and
• the amount of time you'll need to spend working at home after work or on weekends if you can't meet your firm's billable hour requirements solely from your time in the office during the week.

Pretty cool little application, in a kind of fun/scary sort of way.  I did an interview for a profile in JD Bliss that should be coming up in a few weeks.  I’ll alert you when it is posted on the site.