I bought one of these play yards:
North States Industries Superyard XT Gate - North States Industries - Toys "R" Us from toysrus and have used it in all sorts of ways, as an enclosure but also as a gate, especially between rooms with extra wide openings. North States also makes it in both wood and metal now. I think Walmart (online) sells the metal one for less and also has the wood which I have not seen at Toys R Us. I like the flexibility to use this product in so many ways. I would love to have the metal one now, but when I bought it, I needed it for puppies nd they would have gone right through the metal rungs which they couldn't with the plastic grid. Both have benefits.
The plastic ones are very reasonble. I think I got mine for $20 with a Toysrus coupon too!