Newegg offers the refurbished ASUS Black Diamond Dual-Band 802.11n Wireless N600 SOHO Router, model no. RT-N53, for $39.99. Coupon code "EMCAKNP69" drops it to $14.99. With free shipping, that's $24 under the lowest total price we could find for a new unit, although we saw it refurbished for $3 less last summer (via rebate). This is a concurrent dual-band router, meaning it can run two separate full-speed 802.11n wireless networks at the same time. Deal ends January 29.
A 90-day warranty applies, but it is unclear who backs it.