Guest bedrooms are no longer just for guests.

For most of the year, they function as flex spaces for offices, playrooms, dens or craft rooms. But when overnight guests descend for the holidays, it's time to transform those spaces into quiet sleeping quarters as warm and cozy as a fleece robe.

"Clients have been calling me about their kids and family coming home and want to make it really comfortable for them," said Kim Spillum, owner of Kim Spillum Interior Design in Minneapolis. "I'm turning studies and hobby rooms into guest bedrooms."

The always-popular daybed does double duty as a sofa by day and a bed by night. Spillum often chooses models with trundles, which can be pulled out into a double bed.

Katie Bassett of Edina, Minn.-based KBI Design Studios recently outfitted a client's den with an antique daybed covered in velvet bedding -- with a large round bolster pillow that turns it into a comfortable sofa. New French doors can close off the den for sleepovers.

Sleeper sofas in family rooms and multi-use spaces also are making a comeback. That's because today's models are more like slumbering on a cloud than across a metal pole, according to designers and salespeople.

"Technology has really improved the comfort of sleeper sofas," said Tim Mohnkern, sales associate at Baker Napp & Tubbs showroom in Minneapolis. "Manufacturers have redesigned how the bar supports the bed, and mattresses have gotten thicker and firmer."

Today's sleeper sofas are also a lot more stylish. Hancock & Moore manufactures a leather Chesterfield sleeper sofa and many traditional upholstery lines include sleeper sofas.

Bassett recently fulfilled a client's request for an office that also can accommodate her out-of-town parents. The designer created a combination office/guest bedroom by integrating a Techline Studio queen-size Murphy bed and bookshelf system. "When the bed is tucked away, it functions as an office, and there's room for a printer and desk," she said. "When it's folded down, it's pretty and inviting and has a built-in reading light and nightstand."

Guest accommodations don't have to be fancy -- a quiet, restful place to get a good's night's sleep can be enough. Interior designer Brandi Hagen of Minneapolis-based Eminent Interior Design sets out an inflatable air bed when her home is overflowing with holiday visitors. "I always place a table, lamp and water carafe next to it," she said. "I want my relatives to feel comfortable, even though we don't have enough bedrooms for everyone."

And if your guests are early risers, there's one sure-fire way to make them feel at home: Show them where the coffee is stored and how to work the coffeemaker.

More tips

Want to give holiday houseguests a hotel-like experience? Here are more tips:

-- Reading lamp, reading glasses and alarm clock -- set to the correct time -- on a nightstand.

-- Basket filled with travel-size soap, shampoo, toothbrush, toothpaste, mouthwash and Q-tips in the room or a nearby bathroom.

-- Folded fresh towels in an easy-to-find place.

-- Pen and paper in the nightstand drawer.

-- Nightlight.

-- Don't use air fresheners or fragrant candles, because some people are sensitive to scents.

-- Make sure the room and bathroom the guest will be using are both squeaky clean.

-- Empty out dressers and clean out the closet. Add padded or wooden hangers.

-- Set out a luggage rack or a bench with a cushion for suitcases.

-- Inexpensive decorative screens for a family room or basement give guests privacy.

-- Tie a ribbon on pillows labeled "firm" or "soft" and "down" or "hypoallergenic."

-- A water carafe and glass on the nightstand.

-- Blow up the air bed and put on sheets ahead of time, not when guests are there.

-- Lay a nice throw at the end of the bed.

-- Hagen's parents and in-laws stay in a lower-level guest bedroom where it's easy to hear footsteps. "I give them a sound machine to block out noise."

-- Magazines next to the bed for insomniacs.

-- If you have Wi-Fi, share the code for guests' laptops and iPads.

-- Watch for a sale and pick up a robe, just like at a nice hotel.