Of all the lap-friendly keyboard setups I've seen, Corsair's Lapdog looks like the most promising solution for gaming on the couch. It combines a keyboard tray and mousepad on top of memory-foam cushions that sit on your lap.
A wired USB connection links the Lapdog to the host PC, giving folks something to trip over but no batteries to worry about. That USB connection also powers an integrated hub with additional ports for game controllers and other devices. Cabling can be tucked into a channel running along the top, and there's even a bungee for the sizeable mousing surface. The only thing missing is a beverage holder.
Starting in Q4, the Lapdog will be available with an RGB-infused keyboard for $199 or as an empty tray for $89. Although users can add their own keyboards to the stand-alone unit, it looks like compatibility is limited to Corsair's own tenkeyless mechanical offerings. You'll have to add your own mouse, as well.