Just line a closet with Reflectix, or paint it flat white.
Put a "kiddie pool" in it deep enough to contain accidents.
Hang a light with a timer, get some cheap plastic pots, get some decent starter soil and a bottle of grow ferts.
You will also need a fan and/or a ventilation scheme and, depending on your tap water, some PH up or PH down.
Then all you'll need is patience.
We'll be happy to help.
In truth, we all owe you guys.

Aloha,
Weeze