Originally Posted by mae-ling
What type of things would he want to do?
Exactly, a woodworker needs a rather different setup than a jeweler.
But, in general, putting stationary power tools on "flip" carts with wheels can help maximize space utilization. The top of the cart pivots so you can swing either tool up into position and the other hangs upside down out of the way.
You can also build a "work center" out of 2x4s with work surfaces and shelves/drawers/pegboard/etc and then scoot it up against a wall and screw it into the wall to keep it from tipping over.
The carpeting is tough. I'd lay down some heavy mil plastic (painter's drop sheets or vapor barrier) over it, sealing the seams with tape, then two layers of thin plywood, OSB, or MDF, staggering the seams, and then some cheap vinyl flooring. Allow the plastic and vinyl edges to climb the wall a few inches to form a "bathtub" to contain spills. Not sure if the carpet will be crushed and ruined by this after a few years, so perhaps a better choice would be to pull the carpeting up and store it elsewhere so it can be laid back down when you move out.
If he's doing something messy in the laundry room, a series of rods and shower curtains can help keep splatters off your washer and dryer. If he's doing woodworking, get a really good dust collection system.