If you need the circuit to be tiny and a laptop charger is too big, then here's what you can do:
Feed the AC to a diode full wave rectifier. Then feed that output to a 5.1V Zener diode, a capacitor, and (lastly) a resistor all in parallel.
The output voltage across the resistor will be about 5V DC.
You could solder the circuit onto a small proto board or PCB easy.