Hi Danelle!
While I haven't heard of Xbox rentals, there are some great activities at the resorts to give you some "downtown" in the afternoon.
First of all, the Beach Club pool is THE BEST at Walt Disney World. With an incredible Pirate Ship slide, a sandy bottom pool, and lots of poolside activities, I can't imagine experiencing it all in just a few days.
For the video game nuts in the family (I have a 13 year old who has separation anxiety from his xbox), there are arcades at the
Beach Club. Of course, for even more entertainment you can check out DisneyQuest. My fellow Disney Mom Laura tells you all about it in her
Moms Panel answer.
When you check in to your resort, be sure you receive a resort activities calendar. It will list things like pool parties, crafts and even Movies under the Stars.
During the summer, the parks are often open quite late. The
Walt Disney World Calendar lists the park hours and is a great resource.
Hope you have a great trip! And please don't hesitate to let the Moms Panel know if we can help with more details!