1. Make sure that your headlight switch is turned off, and all other internal map/courtesy lights are off.
2. If you have SE&SS/SKS, turn it off using the Smart button under the steering wheel.
3. Make sure that all doors are closed and locked (so that no interior dome light is on.
Assuming that you haven't run down your 12v accessory battery before and it's relatively healthy, 2+ weeks undriven shouldn't be a problem.
Otherwise, follow Toyota's directions to dealers if the car is not to be driven for 10+ days:
http://autos.groups.yahoo.com/group/toy ... 001-01.pdf
US TSB PG001-01: Jan. 12, 2001, Revised Oct. 2, 2003. Maintenance for HV & Auxiliary Batteries at Port & Dealers, 2001-2003 Prius. Replaces TSB PG009-00.
http://autos.groups.yahoo.com/group/toy ... 007-03.pdf
US TSB PG007-03: Oct. 9, 2003, Revised Sept. 16, 2004, Maintenance for HV and Auxiliary Batteries, 2004-2005 Prius
(For the Classic, disconnect the negative terminal on the 12v battery. For the 2004+ Prius, disconnect the wire harness from the fuse box jump location.)
(of course, this'll leave you without your alarm on, and will reset your radio stations and clock, erase stored error codes, maybe erase your consumption screen MPG/odometer, and also disable the auto-up feature on the driver's window...)
You could also go for a 12v battery tender/minder, but make sure you get a "smart" one that won't overcharge the battery, and make sure it provides the proper charging voltage.
There are snowbirds out there that have one Prius up North and one down South, so one sits idle for about 6 months of a year. No problem with the hybrid battery on those times, but the 12v has to be attended to, as does old oil and gas, wear spots on tires, potentially sticking rubber on wiper blades, etc...