My outside electrical outlets just stopped working suddenly, what could be wrong?

Could be a tripped GFI, or it could be one of the outside recepticles or at the panel, then press reset.
Other problems are possible.

joicecannon, Stratmando is right, a GFI usually protects and outside outlet. It should be the outlet itself, but sometimes it is the bathroom outlet protecting the outside outlet. You might check in your bathroom(s) or laundry room or garage for a GFCI that it tripped.